Originally posted by bwDraco
As for the gimbal, the GH-30 looks really nice for the money. I'd suppose it's just a small step down from the WH-200 in terms of build quality.
I haven't tested the Wimberley extensively, but have played with a few gimbals in-store before testing the Oben thoroughly (expect a review sometime in the future on pentaxforums's homepage).
Long story short, I don't find the gimbal lacking in any way.
Originally posted by bwDraco
I have no reason to doubt the integrity of my Arca-Swiss head (it's designed to cope with upwards of 100 lbs of weight), but what's your experience with using a ball head with a large lens? The 150-450 is a bit larger than Canon's 100-400 II, and I'm seeing people use both ball heads and gimbal heads with the latter.
I've tested both the 70-200 and 150-450, and I now own an old Vivitar 120-600mm. These can all be used with a ballhead (using the technique of placing the top plate in the side slot is a good idea if your lens' collar can rotate). For tracking distant subjects with a monopod and ballhead I sometimes simply tilted the monopod as needed
Originally posted by derekkite
Having a long lens on the top of a ball head is very unstable. If you loosen the ball, it will fall over potentially pulling your tripod over.
With a ballhead and a heavy lens you need to tune the friction.
With a properly adjusted/balanced gimbal you only have to follow your subject's movements, it's perfectly natural and easy. It's certainly preferable for larger lenses, however it's an expensive accessory so not for everyone.