I generally prefer a fluid head as some drag is better for smooth movements; and most gimbals do not have good drag. The exceptions are the Gitzo GHFG1 fluid gimbal, the ProMedia Gear Katana (any version), and the Leofoto PG-1 (which is a copy of the Katana Pro). The Gitzo suffers from a lack of adjustability (although there is a hidden adjustment for panning), and the other two suffer from a bit of fussiness (hard to find/set appropriate dampening). Oh, and probably the RRS fluid Gimbal... but I have no experience with it.
Before these Gimbals I was using a UniqBall, but it suffers from not being "hands free" during times of waiting. There is the FlexShooter which is essentially the same thing, but with a fixed counterbalance spring (like a cheap video/fluid head has). The problem with a fixed counterbalance is that it needs to match the weight of your camera/lens... too much or too little resistance can be a problem (can be offset a bit by shifting the camera's CG fore/aft). A head with variable counterbalance is much better, but also more costly.
Before all of them I was using Sachtler video heads... I still have one somewhere. The problem with the better fluid/video heads is size/weight/cost.
So, there's no perfect answer. I've been using the PG-1 for the last few months and I still have my Gitzo GHFG1... I'm kind of undecided as to which one I actually prefer; but I'm going to stick with the PG-1 for a while. I still use the UniqBall for low level/ground work. And I've stopped using the video heads due to size/weight... I'm sure there is a smaller/lighter/cheaper one suitable, especially for use with only one specific body/lens combo (fixed counterbalance); but I haven't looked for it.
