I haven't used the Pachmayr but I've used both Hogue and Limbsaver. The Limbsavers are, by far, the best of the grip sleeves. They do actually reduce felt recoil and being the same price as the others, it's hard to justify using anything else.
The only gloves I have used while shooting were XL mechanic wear gloves, yea I have big hands lol. They don't interfere what so ever with my 21 gen 3. As for grip sleeves, I don't have one on my 21 but I do have the Hogue grips for my desert eagle and they make a night an day difference.