[90°] Elegant beautiful machine that performs as advertised. Really LOVE the lever clamp! and I'm using with 100-400 lens mount in a gimbal mode and it works great! Highly recommend this, and so does HUDSON HENRY.

[1.235 lb] Well built for the price. I wouldn't put anything over a 6" monitor on it.

[Yes] This is a universal quick release clamp and not just for the Acratech products. I also have a similar RSS clamp but prefer the Acratech clamp for several reasons, including: 1: clamp width adjustment is great as it compensates for slightly different, brand-dependent, arc-type plate widths 2: lever has an easy to use locking mechanism to prevent accidental opening of the clamp

[1.235 lb] I have two of these clamps, purchased because there does not seem to be a standard for supposedly Arca Swiss plates. Plates from different manufacturers differ in width, whereas, a typical lever clamp is designed for a specific width clamp. This means that plates that are too narrow can slip out of the clamp and plates that are too width are difficult to clamp in. The Acratech clamp solves this problem by making an adjustment for plate width.
In addition, the Acratech clamp has a secure and easy to operating locking mechanism for the lever to prevent accidental release.

[Yes] Was surprised at how well it was built for the price.

[Yes] I have been shooting landscapes for over 25 years with a ball heads, using the best ball heads available. Then I tried geared heads but the movements were slow and limited.
This Acratech Pano head is better for pano photography than all of them, The movements are smooth as silk.
The clamp locks and can't be accidentally opened such as with a camera bag strap. 
The clamp can easily be rotated for a different orientation.
There is a moveable marker on the base to set your pano starting point. 
The knobs are large and easy to use even with gloves on. 
In my image is the head on the Acratech Leveling Base on a Really Right Stuff TVC-34L tripod.

[Yes] I am using this video adapter on a Manfrotto MVH-500AH. I want to avoid using multiple plates both for cost and reduce carrying additional plates with Acra heads. The main issue was the position of my Arca Swiss plate which is in a horizontal position. Switching to my 70-200 requires switching to a vertical position. This is the only plate I found which allows the position to change in a quick and efficient manner. The plate is sturdy with no movement.

[Yes] I have hesitated to do any wildlife video just because it was such a hassle to put the arca-style quick release / lens onto my video head's screw mount. This little piece totally solves the prob - I sat with my video tripod and Sony A9+100-400 and did some cool video with monarch caterpillars on my first-time milkweed. Piece of cake mounting/unmounting the rig. I LOVE the adapter.

[Yes] I purchased the Acratech GXP-SS ball head mainly for macro work with the 200mm f/4 Micro-Nikkor and for telephoto work with a Nikon 500 f/5.6E PF lens because of its imitation of a Gimbal head - for subjects that require longer wait times than my arms tolerate. It performs amazingly well in both applications and has the added benefit of being ultra light and easily cleaned unlike most ball heads. I am pleased!

[Ball Head] If you have a lot of money invested in your Arca-Swiss style camera brackets and lens rails, a perfect way to adapt your gear to a video fluid head. You can switch from still to video very quickly without having to remove your brackets or rails.