I bought Mullers for my Benelli SS. They do not collect plastic or lead, they stay tight, they pattern at least as well as any other system and I really like that Muller makes only a few constrictions and keeps it simple. Besides that, there are no ports, wad stoppers or other gimmicks, just a well thought out choke that does a good job.
They look nice to boot. A bit pricey, but a good product.
I have to admit, that I would never have bought Muller chokes, because I really didn't see the big deal. I ended up shooting on a squad with Jim Muller. We talked a bit, he didn't talk nonsense and he is a straight up guy. So I tried his chokes. Glad I did.