I recently got a Vanguard Auctus Plus 283AT Aluminum Tripod (I put a review in the database; TL;DR= I love it; gear driven center post!).
So I needed a ball head. I have one on my Dolica travel tripod, which basically is meh, and the quick release plate is awful (proprietary, not Arca, but it works the same way, just the wrong width).
I wanted Arca, and big and solid, and it's really tough comparing them, since weight specs are totally illusory. I was nosing around a SunwayFoto XB-44 when I discovered that there are sorta clones of this unit. A very helpful Amazon reviewer had noticed that Desmond products seemed to be essentially the same, and reviewed a Desmond DB-44 ball head, for $75 at Amazon (Anthony M is the user; props to him). On that recommendation I got one, although with the cammed quick release instead of friction knob. And he's right; it's unbeatable for the price. Comes in crappy packaging with no instructions, but boy, what a deal.
The quick release is fully Arca compatible, and works very well. I was worried, since cams can be too lightweight in some instances but this is quite beefy, and adjustable (just turn the lever, although in the opposite direction than you'd expect IIRC). It's got two slots, so you get more versatility in positioning the camera, but you don't sacrifice stability. The friction of the knob can be adjusted, so that you don't need much of a twist to lock or release. You usually don't get that except on more expensive heads, or the ones with two knobs, which sometimes don't work well. So you can have one setting for that big-a** lens and another for the 40mm XS. Movement is quite silky.
On the negative side, no instructions, although you can google around for info, and it's pretty self explanatory. The lube is a bit obnoxious; I may change that.
The Desmond plates and hardware is also top notch. No funky threads or cheapo screws with wobbly Allen sockets. I have an L Arca bracket and it's wonderful, and even got a ball head attachment to flip the ball head upside down (much cheaper than springing for fancy levellers). They make a combo friction screw/cam lever quick release plate; wish I'd gotten that.
The distributor's pages are here:
Desmond Photographic Distributors. Much of their stuff is sold through OEC Camera with Amazon fulfilling, or slightly cheaper on eBay under that same name. Very decent folks to deal with.
We'll see if this ball head stands the test of time, but I am very impressed so far. And it's a good match for my Vanguard tripod legs.