Put in the camp of not caring for the pistol grip. As mentioned by Horniac, my spotter (swaro 65 sts) was too heavy for it. It wasn't smooth when moving it, which made it difficult for me to systematically cover the country I was glassing. Finally, I didn't like pulling the trigger all the time to move it.
I have their pan head and really like them. In fact, I like them so much I own two of them. I have gone away from their binocular stud and adapter and went with Really Right Stuff polymer cinch. I found it helpful in reducing neck strain when glassing with my 10s & 15s when using a window mount. It sits the binocular further back, which also makes it more comfortable when glassing from a tripod. I use the Outdoorsmans adapter plate with the cinch.
I would encourage getting the panner if you are set on getting the pistol grip. I didn't have the panner with my pistol grip, which probably contributed to my issues.