The only "hydraulic" heads on the market as far as I know, are the Evans Oilheads - but isn't that a misnomer? They have some kind of oil between the two layers of head - that is why they are so dead.
I haven't tried Attack heads, but I have heard decent things about their "clear coated" heads - I don't think they actually make them anymore - they are the "DW" heads with the white coating ring on them.
I'm still partial to clear Pinstripes. I guess once you get a sound you like, you just stick with it.
Tim