Check out the military forum and do a search. You'll find a wealth of information there, including some information the recruiter may or may not have told you. There are definitely pros and cons to doing the HPSP so you have to be sure of what you are doing and make an informed decision. That said, I'm a 1st year HPSP student and I know I made the right decision for me.
Since you posted this question in two forums... I thought I would answer it in both. Here are a few things to think about if you are ready to sign up:
1) HPSP may not pan out if you only do it for the money. Army docs make much less then civilian docs and, given the time frame to repay Uncle Sam, you could have paid off your student loans in the civilian world.
2) HPSP may restrict your specialization and in some cases make it difficult to go into anything other than a GMO.
3) May still have to take out loans to cover additional expenses while in med school that the HPSP does not cover.
4) One word... Iraq (or any number of other overseas military zones)
5) Lastly, it may seem like a great idea now, but can you speak for yourself 4-8years in the future? In other words, do you know that in 4-8 years you will still want to play "GI Joe"?
These items are not meant to start a war... only offer a few things to think about. In the end it is up to you and if you are willing to make the commitment and are dedicated to serving your country then more power to you. The military needs you!