well...I am actually transferring from one of the top 20, due to a family reason. so far, desperate.
some personal tips to those who are about to decide where to go (that I did not know when I decided):
--Do NOT choose very countryside school regardless of its ranking, if you are a city person and think diversity is important.
--Check how many grad students drops from the program. It means not only the program is harsh (or naive) but also it means it is less friendly overall.
--Weather is a lot more important than you think.
--If you have money, then getting funding from the program is little important. If the school gives funding but does not satisfy the above three, don't go there.
Remember it takes (at least) 5 years in ph.ding....