the K after the cpu means that it is unlocked and able to be overclocked
the S after the cpu means that theres a little lower performance in exchange for lower power draw.
and T after the cpu means Power-optimized lifestyle" - much lower performance, but also much lower power draw.
so i would agree with tennis on this one
Yes, since I own a Z series board (Z77), I purchased a 3770 (plain) for $50 (USA) since it can be OC'd +4x on the multiplier, resulting in 4.3GHz for 1&2 cores loaded, 4.2GHz for 3 cores loaded, and 4.1GHz for all cores loaded. I could go further with BCLK increases, but I chose not to due to instability risk in BCLK adjustments on Ivy Bridge.
It was a nice little upgrade from my 3570K which was only getting 4.2-4.3GHz all-core anyway. I could've sold that chip to recoup most of my upgrade costs, but I needed a chip to upgrade my grandma's comp. Hopefully the 3770 tides me over until late 2021 and DDR5.....we'll see.