910xt or Ambit 2???

It sounds like you already know the pros and cons of each watch pretty well.  I've been a garmin guy, but ended up grabbing an Ambit2S a few weeks ago.  Like you've indicated, they each have their own features.

I have no problem living without a vibration alert.  The Ambit2 does have a basic interval training feature (haven't used it tho') but certainly, the custom workout creator is a great feature of the garmin.  it's so rare that I ever do that kind of training tho so I don't miss it.  (Plus, I still have my 405 for track days).

Some things that I like about the Ambit (YMMV)

- It's a watch.  i.e. you can wear it as a watch.  it looks like a watch and acts like a watch.

- Some new and interesting HR based training stress metrics (EPOC, PTE and Recovery Time).  Pretty cool. You can lay in your specific and tested HR zones and athletic levels so that it calculates your training stress off of these.  There is some good white paper backup for these metrics as well- still learning.

- the Movescount web site- I think is better than Garmin's.  yes, you can export .gpx files out of it..

- navigation routes and trackback function.  works well and you can choose to add navigation to any sport.  Easy to create routes and send them to the watch. it has reliably allowed me to stay on course through difficult trails.  Oh, you can not only retrace the steps you just took, but you can select any route previously run that's in your logbook, and re-trace those steps as well.  Unfortunately- not with a virtual racer or pacer tho'.  Seems this could be in a possible firmware update tho?

- selection of customized sports.  Via the web site, you can set up a selection of screens and parameters and designate that selection for individual sports.  So, it's not just a 'swim bike run' watch.  You might want to go skiing and have it display speed, vertical and number of runs- for instance, and you can label that sport 'skiing'.  I recently set up one called 'sleeping' that just records my HR while sleeping.  Granted, you can program in screens on your 910 to do these things as well- but, this way you can have them all set up in advance.

-ability to extend battery life in GPS mode by choosing 1s, 5s or 60s GPS recording.

- swim mode.  I find it works better than the 910xt's.  When I swam with the 910 it often seemed to show I was on the wrong lap, and then after I was done with the set, it 'caught up'.  The Ambit has been dead on every time, and after you train it, it even accurately tells you what stroke you were swimming.  

-Fused pace.  it uses an internal accelerometer as well as the GPS to determine your pace.  So, instantaneous pace is more stable than Garmins- especially if you run under a bridge or in sketchy GPS areas.

- super fast GPS lock.  since it downloads the next 3 days of satellite info, even if you get on a plane and start it up the next day 1000 miles away- it locks up to satellites in seconds.  nice.  (recently tested this too)

- apps.  I guess one of the cool features of the Ambit's are that you can download from the 1000 apps that people have created for it.  From my limited check of them, 950 of them are just garbage.  There's not really that much so far in the app department.  Actually, I found a good skiing one, but for the most part, they're mostly too amateurish.  Still- a lot of potential there though.

Downsides:  no custom workouts, no vibration alert, no virtual pacer/racer, only displays 3 variables at a time (but plenty of screens and the option to scroll through the bottom item of your main screen - so really pretty good here).  Not quite as directly compatible with all other web sites.  Like, in order to link with strava, I need to export the gpx file from movescount, and then upload it into Strava.  it doesn't do it automatically like the garmins.  this may change in the future of course.

Other downside.  If you want to change which variables are on which screens and in which position... you need to use the website.  Can't do it from the watch.  This was annoying during my 1st week, until I got the watch set up the way I like it.  But- this is also an upside.  it's easier to set these things up via the web interface- and you can set up dozens of selected or custom sports, and then download just those that you need to your watch.  So- 'skiing' doesn't need to appear on your watch during the summer when you're never going to use it.  but come winter time, you could set separate sports for Skiing, Snowshoeing, Cross country skiing, and ice skating- as examples and have them available on your watch, but not have it show open water swimming- for instance.  

Like you've learned- they each have their features.  The Ambit 2 not only competes with the 910xt- but is also a direct competitor to the Fenix/Tactix watches.  If you're a pure triathlete and want a single device that captures all your swim/bike/run and otherwise not having it on your wrist, then get the 910xt.  If you venture into other sports, like trekking, ultras and like to play with a more versatile device on your wrist, then maybe the Ambit 2 is for you.

keep us posted

update.  virtual pacer (fixed pace) is something that can be added to the Ambit2 via apps.  There are a number of public apps that do this function.

The new polar v800 (not available for another few months) will have the Fitbit style activity monitor and presumably step counter built into it.  So- maybe wait for that watch?.  You can wear it all the time and it will have that capability and fuse your total 'activity' with your training.  I guess that's a nice feature.  Frankly, if you're doing serious swim/bike/run training 8-12 hours a week, there's little additional fitness benefit that you're going to get from how much walking you do- as the intensity level is too low.  (that said, there may be real health benefits to lots of low level activity- just not performance benefits)

Theoretically, since the Ambit2 has an internal accelerometer, it could be programmed to do this.  i don't believe that the accelerometer outputs are available for the creation of custom apps tho'.  This would have to be added in firmware by Suunto, and I wouldn't think that was high on their list.  

I am, however, hoping they will add not a step counter, but a cadence output.  Which certainly could be added based on arm movements.  Got my fingers crossed on this.  They've made a few excellent firmware upgrades so far on the watch, which has already improved it significantly.  Not sure what else is in store, as they'll probably be announcing an Ambit3 later this year- 'cause that's what companies do.  

I am impressed with the ease with which via Garmin Connect, you can create a pretty complex custom workout with various times, distances, HR or pace limits for a full custom workout, and send it to your watch to take you though.  If you do a lot of these- I think that puts you squarely in the Garmin camp.  it's a great feature and well executed.  I've used this on my garmin and it makes track workouts fun.  That said- I rarely do those any more.  Plus, I still have my garmin for those days.

if you're interested in the V800, you should read Ray's quick look review:  http://www.dcrainmaker.com/2014/01/polar-v800-triathlon.html

No- I don't expect it will have ALL the other functions of the 910xt or Ambit2- but it will have different ones.

Yes, it will be able to swim, bike and run

the key thing about it is that it will be able to record heart rate while swimming.

Originally posted by LGPS-BR .. Swimming with the Ambit (or any other watch) is a new thing for me, and it is perfect, now I can compare trainings and this is really great. as it's about 40 degrees Celsius here in Rio de Janeiro swimming is the main sport for me now ...

Once I 'trained' the watch, selected my choice of displays and figured out how to use it while swimming, (like, not to keep hitting the lap button or start/stop), I've found it to be very accurate and my favorite swimming watch.  Big clear display that shows just what I want when I want to see it, and a mostly 'hands off' operation.

Since it's warm where you live, and you have a nice ocean- have you tried out its accuracy in open water swimming (vs pool swimming?).  

If you happen to have any other GPS watch, sticking it in your bathing cap works very well.  So, you can compare the tracks.  Or- just looking at how jagged the track is- often answers the question as well.