The 3570K is definitely a winner!
As stated by noise, Overclocking will be limited (to about 4.1Ghz max with a tower cooler like evo 212). And if you'll be getting a PCIE 3.0 motherboard and graphics card, then theres nothing that should stop you from getting an Ivy Bridge CPU.
You can also use Virtu MVP which uses your iGPU (HD4000 for the IB) and pairs it with your dedicated Graphics Card. Virtu MVP is only available for IB! So be careful.
If you dont need Virtu MVP.. or dont have a Z77 motherboard or a Z68 motherboard with PCIE 3.0..
Then.. Sandy Bridge is much better!
- Im currently rocking a 3570K with a CM 212 EVO and a Z77X-D3H Motherboard.