Having a Carlson extended Mobil choke in the upper and a Briley extended Mobil choke in the lower barrel of my 28 Gauge O/U, I prefer the Carlson for three reasons.
1) The Carlson choke measures spot on to it's advertised constriction, and the Briley is slightly off. This via Telescoping Bore Gage measure.
2) The Carlson fits perfectly, but the Briley is a bit oversize or off in some way in the thread department, and it is a major effort to install and remove it. I thought this might be a function of the threading on my barrels, but reversing them results in the same struggle for the Briley and ease of fit for the Carlson.
3) The Carlson subjectively looks nicer, mainly because it extends farther out, but up close it also appears to be a bit nicer finished, or finished with a bit more care and attention to craftsmanship.