Do they work fantastically well for pin scars? Yes! Are they 25% cheaper than the closest comparable product? Yes! Will they hold a fall, and are they built very well? Yes! Very flexible? Yes. And will they work for placements other than pin scars? Yes! Although the purple/blue and blue/yellow are my go-tos for pin scars, the larger sizes work very well in irregular rock, especially in the east where quartzite is prevalent. Think Seneca rocks and Moore's wall. If you see a good cam placement, but two lobes are just a little more flared than you like, go for the Master Offsets! They'll fit great!
Master Cams rock! (I know, that was lame...) I've been adding a set of Offsets to my rack for pin scars and non-parallel cracks (my gear currently consists of C4s .5-3 (2 each), with a single 4 and 5, plus a set of regular Master Cams 00-4...and of course nuts, gotta have nuts). I love the C4/Master Cam combo, I think it's the best bang for the buck and all-around best gear on the market right now.
I was bummed like everyone else (except those who are ebaying Aliens for $100+) about CCH's demise, but salvation has arrived! The offset Metolius cams are better, IMHO. Recently I was on El Cap and Leaning Tower, and we had sets of Master Cams, Offset MCs, Offset TCUs, Aliens, and Offset Aliens.Bottom line: I can remember several placements where the Metolius cams worked and Aliens didn't, including one where an Alien (black/blue) popped, sending me for a flyer. I went back up, finagled in a Metolius Offset, and continued climbing without incident. Fit and finish is spectacular as well--easily as good as Camalots, and far better than the stoner-built Aliens.
These are definitely a specialty piece. They fit in pin scars where nothing else will go except for a cam hook or sawed angle. If that's what you need, then they are the ticket. For climbing in the Valley, my favorites are the blue/yellow and yellow/orange. I rarely bring them free climbing unless I know that I'll be climbing something with a lot of pin scars (Serenity Crack, etc.) They really shine while aid climbing when you can't just run it out to the next straightforward placement. My only complaint is that the plastic on the thumb loop has torn open on several of mine from clipping into it directly (this is a cosmetic problem only.)