I have both The Pro Diamond, and the Extreme. I will say I like them both, and have shot them both on my hunting bow a lot or the past 5 seasons. The Extreme is a little shorter, but has a beefier handle to it. The standard Pro Diamond has a slightly smaller frame and smaller finger grooves, but a longer neck on it at the caliper. I would venture to say you'll like the feel of the standard version more.

They are smooth, but require some lubrication once in while to keep them that way. Mine see the elemants out in the woods; rain, snow, dirt etc. and I've never had them fail. But they will get gritty from that, and you have to disassemble them, clean them up and lube it before reassembling. Not a bid deal, I do it once before hunting season, and I'm good to go.

I don't know how much you want to spend, or what you're using it for, but this release below is an excellent model, and they build it in a smaller frame. I've used it myself. It's great for target, not sure if I'd hunt with it though.

http://www.ishootastan.com/index.php?option=com_content&task=view&id= 15&Itemid=29

I forgot the others you listed............the top one fires with back tension, no trigger.....not good for hunting. The 2nd one, the release fires with depressing the thumb trigger down, while the Pro Diamonds you will pull the trigger back with your thumb. And the 3rd, is also similar to the Pro Diamond, but with a much better trigger assembly. It will load by pushing the silver bar on the back of the release, making a loud "snap" so I would consider it great for target, but no hunting.