For the money its hard for me to really go for it like I want to! PLUS at ATA show last year I grabbed a Ramcat and tried to put on in and I didn't like at ALL how they fit in the hood! An expandable would have been fine BUT I like my Ramcats WAY too much!!
I have had the one piece ATX mounted directly over the Montana Black Gold Sight on my Carbon Element. It was noisier than my the Tightspot and sits further out from the riser. Other than that it worked flawlessly over a couple of seasons. If buying one today I would get the Tightspot. I go on two week backpack trips where I weigh everything down to the ounce (ATX is 3 ounces or so lighter than the TS) and don't like to add weight, but in this case think the TS is worth it.