There is no "one" criteria you can look at to decide. I believe a clinical education touches on many areas, and each is more/less important....dependent on what the person wants.
1. Match Rates I'd be concerned with any program that can't even make the national average year in and year out. There may be some fluctuation because of isolated instances (for instance....match rates at my school were effected by wilma/katrina, but bounced back to 87% this past year) Stuff happens.
2. Research If you want to do research in a certain area, you'd be foolish to go to a program that doesn't support work in your area, and/or a place that doesn't put an emphasis on research. (My own bias is that I think programs need to be balanced, because I believe both research and clinical experience are equally important)
3. Clinical Schools can vary greatly in their training. Make sure to ask around the psych community and/or places you are interested in work about each school's clinical reputation. There are some great programs out there who do better jobs than others in this area. Just because you go to a research program DOESN"T mean you will not get quality clinical training. Just like going to a great clinical program doesn't imply you won't get quality research training. Be wary of any school that outwardly discounts one area to the detriment of the other.
4. Cost I consider cost to be both time and money. One thing that scared me (as someone changing careers) was the rising cost of education and also the time required to complete training/research. I use to golf with someone who was in his 7-8th year or research for his dissertation, and he was just finishing up. He was teaching at the time...so he did it slowly, but if you want to do clinical work, you need to finish, get licensed, etc. That being said, I wanted solid clinical AND research opportunities, so I needed a balanced program.
5. Reputation This is very subjective....but also important. You want to go somewhere that has a good reputation for what you want to do. Many times there are great supervisors at average programs, and average supervisors at great programs. It'd be nice if they were good/good and great/great, but most places aren't like that. DO YOUR RESEARCH!
6. Location This matters more to some than others. In retrospect, I learned about a number of great programs that I didn't previously consider because of their location. Some people have restrictions because of family, etc. If you don't have that constraint, you should really base your choices more on the other areas......to be honest, you won't have much time for a social life anyway!
*added*
7. Opportunity: Often times life happens. For instance....the POI you wanted to work with goes on sabbatical, you landed 2nd on the list of multiple programs, your top choices end up being not what you thought, etc. I am a believer that top people can be successful most anywhere they go.....but it sure is nice when it isn't all up hill.
I'm sure there are more, but I need to start on some paperwork...blah.
-t