I was in your exact same position several months ago. I'm in college and on a somewhat limited budget, but I really wanted a nice set of racing wheels. The HED3's were very appealing mainly because they are often described as "the most aerodynamic wheel besides a disc" and seem to be somewhat versitile because they are not solid (as a disc is). I finally was able to buy a set a month ago and so far the differences have been unbelieveable. Heres a few of the pros and cons as I have noticed so far.

Pros
- I am able to maintain higher speeds longer and seem to have more momentum coming into a hill.
- They are stiffer than my spoked wheels I use for training so they feel much more responsive.
- They're a lot lighter.
- If you get the regular HED3 (not the HED3 full carbon wheels) they will still have a carbon wheel but the outer rim will be aluminum so you wont have to buy new break pads.
- The set I bought are tubular and being able to get the tubes to higher pressures helps w/rolling resistance (not sure if I have really noticed this or if its just in my mind).
- They look bad ass.

Cons
- Crosswinds - I'm a heavier rider (180 lbs) so this doesn't effect me as much as a lighter rider but it is noticeable.
- They are a bit expensive.

My suggestion to you would be to keep an eye on the classified seciton of the slowtwitch.com forum. I bought my wheels from a guy getting ready to start grad school who was getting rid of some of his stuff and I was able to save close to $500 on a lightly used wheelset (they had less than 200 miles on them). Heres a pic of the bike. Feel free to pm me if you have any questions.