Best Cycle Computer

I have the Astrale 8 wired by Cateye, and I got stuck in a decent rainy condition and how my cadence is completely fried.  Everything else works fine but the cadence.  Bummer

Looking at other options. 

Why can't you use it on the trainer?  If you've got the speed and cadence sensor installed, just turn off the GPS and it'll use that for your speed and distance measurements while on the trainer. 

I love my 305!!!

The sensor actually has both speed/distance and cadence.  One magnet goes on a spoke on the rear wheel and the other goes on the crank arm.  It's a little difficult to install it at first because you have to get all of it to line up correctly, but once it's done it's great.  Take it outside for a ride and it'll even calibrate itself automatically using the GPS. 

Did you get the quick release kit too?

I have a Garmin Edge 305 (I actually have two of them but that's a long story).  I have had to send it back a few times but Garmin has been excellent about replacing it.  It is great to get accurate distances plus heart rate and cadence all in the same uploadable data set.  With the cadence/speed sensor, it works on the trainer too.   I am not crazy about the computer software for analyzing the data after the rideand it takes a while for the GPS to find it's satellites before you  can push off.   I use it for just about every ride.  Disclaimer.  I am a major geek about gadgets and data.  People who aren't may not like the Garmin.

TW 

I have the Forerunner 305 with the quick release kit.  I can wear it under the swim cap during the swim, then click it onto the bike in T1 and finally click it onto my wrist in T2. 

Garmin's training center software that comes with the watch is really not that useful.  However, I've got a free account with MotionBased.com that I upload all my data to and I love that.  You should try that out.