Go check out a breakdown vid and take a look at the cooling system of the Phat PS3. Then realize they frequently are putting out 100C+, hotter than most gaming laptops.
With the tin solder problems, it'll fail eventually. If there's a trade in deal that makes a new system cost about as much as a crappy refurb, I HIGHLY suggest you take it.
From a guy thats gone through 2 PS3's and very expensive SXRD Sony television in just the past 5 years. Sony hardware QA from 07-08 crap.