IM Florida v. IM Louisville

I did both races in 2009. 

IMKY was my first stab at a 140.6.  I DNF'd at mile 18 in the marathon.  I competed in and completed IMFL 2 months later.

Here are some of my thoughts: 

• Time trial start at IMKY - I actually liked this.  There wasn't the mass chaos that comes with a beach start, and the whole "washing machine" thing was not quite the same.  In fact, I had clear water for almost the entire swim.  The PIA piece about the start here is that you have to line up several hours prior to the start in order to maximize your "on the course" time.  Not a big deal if you're not planning on being in the 16-17 hour range.
• I personally didn't think that Louisville had "rolling hills".  Then again, I'm from Florida, and we don't have hills where I live.  I was woefully underprepared for the constant climbing.  In fact, this alone killed my race and was the proximate cause to my DNF.
• In 2009, the weather was perfect.  Of course, it was probably an exception to the rule.
• The finish line at IMKY is spectacular.  Far better than the finish at Florida
• The swim at Florida was fairly rough in 2009; the 2nd lap was choppy, and the whole melee thing was "interesting"
• The bike in FL is not pancake flat - there are false flats and a few small hills.  The wind is only tough in a couple of stretches. 
• I actually think the fan support at IMFL was better than IMKY...especially on the marathon course.
• If you'd like more of my perspective on IMFL, see my race reports here, here, and here.

All in all, I really enjoyed both races...though I would have liked IMKY better if I had been able to finish it.

Good luck w/ your decision and with your upcoming race.

I am doing IM Lou this year and I haven't done IMFL.   I did do B2B iron distance last year , and it is similar to IMFL because it's the same day and flat windy bike.

I liked training for a November IM a lot more than the end of August.   You will have the spring to work on building up your bike fitness without having to get on the dreaded trainer.  Also, the final 2 months are with cooler temps.  It can be miserably hot training for IM Lou.

I think Lou's bike course fits me better though.  I ride a lot of hills, but rarely ever ride flats.  At B2B I was not prepared to sit in aero for 6+ hours.  I was bored and stiff.  If I do FL in the future, I know I will need to do my long rides on very flat courses to get used to that.

IM lou in 2009 had cool weather (high of 70ish?) while 2010 it hit 95 degrees. 

btw, I do better than most folks in the heat, but once it got that hot it was really tough to keep it together.  I've never seen so many people sprawled out on the side of a course as I did at Lou this year.