Up for sale is a Pro Gear gimbal and grip for 1.5" posts. I've been told that this is basically a copy of GPI's PRO gimbal, in terms of design. As for function, all I can say is that it works. It seems to work well. Pan and tilt feel smooth, there's no felt friction or vibrations, and it doesn't make any noise.
It seems to be field serviceable, as you can see in the pics attached. I'm not sure if the PRO gimbal tool works with this one, but you can break down the major components, including the main pan bearing, which you can also access, clean, and/or replace. The yoke fork bearings are accessible by removing the bearing caps, which are just screwed into place.
Is it as good as a real PRO? I've never used a PRO gimbal, so I can't compare, but I can't imagine that something that is an off brand copy is ever really as good as the real deal. I certainly wouldn't buy this thinking it would be.
That being said, buyer beware -- apparently, there's a long and sordid history with the company that produced these gimbals (Pro Gear). You can search for it on the forum, but the long and short of it seems to be that the company was really, really bad with customer service. And the bottom line is the company is no longer in business.
So if you're looking to get it serviced, you're probably on your own. You won't find support from the manufacturer.
Looking for $1000, but I'm open to offers! Drop me a line here, or mail me at firstname.lastname@example.org
Thanks for looking!