This is a little long, so my short point is at the end of each paragraph for easier reading.
I went the CC route myself for two years--dual enrollment beginning after my junior year of HS--then transferred to a four year college when I finished my associate's degree. It's a really good deal for all the reasons people have listed--smaller class sizes, much cheaper, etc. Also, as others have said, so long as when you do transfer you maintain a high GPA in your classes, no medical school will look down on you. Simple fact is that education is very, very expensive, especially graduate level--if you can start at a CC and transfer to a state school, you'll have less stress than someone with an outstanding 50-100k in student loans from undergrad. Bottom line: keep it cheap now and you're being financially smart.
As comparisons go (and let me be clear that this is all from personal experience), I actually prefer the two CC's to the two university's I have attended. The average student was older--people had more life experience and were more motivated to improve their lives as a whole than your average fresh out of high school kid going on mom and dad's dime/out in the real world for the first time and partying hard. It was a place where I had an easier time finding a community of like-minded people. Certainly there were those who slacked off and one could call 'dumb as rocks,' but the environment was good overall. It was an easier transition for me and I met a lot of cool people. Bottom line: you'll still get a good community experience as well.
Academics wise, don't worry about transferring credits within your state. Most (maybe all?) states have agreements with community colleges. If you finish an associate's at one of their CC's and then go to their state school, everything will automatically transfer. One caveat: it will be guaranteed to transfer, but it's probably a good idea to figure out which university you want to transfer to now so you can look at the classes required for their four year degrees and make sure that the classes you're transferring are the ones you actually need. Ex. Bio 101, 102, and 103 will transfer--but they may transfer as non-major biology if your CC offers, say, 181/2/3 for 'majors' instead. Bottom line: make sure what you're taking in fact covers your pre-reqs. Not normally a HUGE issue though--I personally had no problem.
A major problem I did encounter at CC was the issue of self-motivation. It's not that the subjects have somehow become easier at a CC. They haven't. However, the standards are often much more lenient, so the average 'smart kid' can get high grades with less work than a university counterpart. I was pretty shocked by how much more I needed to know when I got to university to ace exams. At a CC, you have got to self-motivate. No one will hold your hand to get to that higher bar. There's a lot of 'plug and chug' type exams that are really easy to cram and brain dump the info from afterwards while still doing well. If you can force yourself to learn things and retain them, you'll set yourself up for success and profs will often single you out to help you. Bottom line: aim to master material, even if the course doesn't necessarily 'require' it in our pre-reqs; you'll thank yourself come MCAT time.