[ QUOTE ]
let's talk abotu a reasonable range for villian in hand 4. He's 20/9, he open limped in MP, called a raise, the checkraised the Ad 2h Th flop.

How's: A2s+, QhJh, Jh9h, A9o+?

If that's good then it's indeed to call the flop checkraise getting 8:1, and fold the turn getting ~6:1

Flop:
Board: Ad Th 2h
Dead:

equity (%) win (%) tie (%)
Hand 1: 19.2466 % 19.08% 00.17% { KhQs }
Hand 2: 80.7534 % 80.59% 00.17% { A2s+, QhJh, Jh9h, A9o+ }


Turn:
Board: Ad Th 2h 5d
Dead:

equity (%) win (%) tie (%)
Hand 1: 10.2740 % 10.27% 00.00% { KhQs }
Hand 2: 89.7260 % 89.73% 00.00% { A2s+, QhJh, Jh9h, A9o+ }

[/ QUOTE ]
The range of the villain's hand is irrelevant to me. If I believe that I will get a free card by 3 betting the flop, then 3 betting the flop is clearly betting than calling. If the hero has the odds to call one small bet on the flop, then it makes sense to 3 bet and pay two small bets to see the river. But this play is risky, it wont always work out as perfectly as I outlined since ther hero could easly get capped or get bet into on the turn which is why to make this play the hero needs to choose his opponents carefully. Against the right opponent, 3 betting with a gutshot definitely has its place.