I can get them both at the same price. My guess is a Sandy with the H60 waterblock, rather then a 3570k with a 212 Evo. But people have been telling me conflicting things. At the very least, 4.7GHz sounds more impressive then a 4.2 on a ivy.
Honestly... They perform about the same.
The 2500k has more overclocking headroom.
The 3570K is more efficient in power use... but an OCed 2500K and an OCed 3570K are about the same in all regards.
If I had the choice I'd go for the slightly newer architecture.
The H60 and the 212 Evo are just about even in performance anyway (the H60 is ~1C cooler, on average), so I would just save my money and get the 212 Evo, as far as the cooler is concerned.
As far as the CPU is concerned, I prefer the 2500K (obviously, lol), but the 3570K is probably the better choice.
For what it's worth, a 212 Evo or H60 will get you to the same clocks on either CPU (4.3-ish with the 3570K and 4.5, easily with the 2500K, with a decent chance at 4.7-4.8, depending on voltage and room temp).
I agree about the Corsair H60 to some degree. I've got an H70 on a 2500K and a Hyper 212+ on a 2500K. The H70 allowed for an overclock of 4.75 Ghz. The 2500K with the 212+ was only able to get the 2500K to 4.5 Ghz.
It is pretty close but there is a difference ever so slight...