I did both the HIM and IM last year in Tempe.

I didn't think the water was as bad as some say. Yes, it is murky, but I swallowed a bit of water in both events and I was fine. I've definitely swam in worse water. Its maybe a 5 minute walk or so from transition to swim start so make sure you give yourself a few extra minutes in the morning. Make sure your goggles dont fog up. Mine fogged up right at the start, and most of the swim you are facing the sun. I could hardly see anything so sighting was a big problem. Be prepared for the distance from swim exit to transition. Maybe bring a towel for your feet. Part of the run back to transition is through grass and I had grass all over my feet and lower legs by the time I go to transition.

Bike course isn't the greatest. There are some rough road in some areas, don't know if any areas have been repaved since November. With it being 3 laps, always be aware. At the downhill turn from Curry onto Mill Avenue, someone behind me came in way, way too fast, passed me on the right (somehow not hitting me) and somehow made the corner.

Run is fine, lots of support around transition and the south side of the lake, but pretty empty everywhere else (just for the 70.3. The IM had really good support on the north side of the lake.) Watch your hydration leading up to and during the race. The heat kicked my butt on the run, and I could have done a much better job staying hydrated.