The only one I've tested is the Comp-N-Choke in a 12ga Mod and I didn't see any significant difference at the pattern board over my regular Browning Extended Midas grade chokes.
One of the guys at my club had bought a few of the Comp-N-Chokes - and he thought they were a little tighter - so we swapped chokes and each put three shells thru each gun - and we didn't see any obvious difference.
I think he paid about $ 50 apiece for the Comp-N-Choke and the Browning Midas grade sells for about the same. Browning has a new Diana Grade choke out now too - for about $ 60 claiming superior performance as well - my opinion is its mostly marketing.
Once you pattern a gun and you have a set of chokes that perform to your expectations / I can't really see replacing them. I can tell you there is a little variation in my box of chokes ( I have 3 choke boxes for my 12ga Brownings - each with 2 skeet, 2 IC, 2 Mod, 1 IM, 1 Full ) so if one of the boys is with me, and borrowing a gun, he gets his own chokes - but there is a little difference in the chokes where among 3 Mod chokes - they can be a few thousands difference between them. So you really have to know the measurement difference between the inside of the barrel on the specific gun and then measure the choke. There is more difference that I imagined in a variety of 12ga Brownings that I have ( an old BT 100, a couple of BT 99's, a couple of XT's, 3 XS Skeets ....) all 12ga's but not all the barrels are the same inside dimension.
I like extended chokes but I don't think there is really a big quality difference from Browning, Briley, Comp-N-Choke, etc - I would just recommend you go with one brand of extended Chokes and be done with it.
