I've had a variety down the years. I've a Stanley handled one that used to be good but now slips - pretty much worn out, I think.
I bought a Draper concertina-type some years ago, and it's been brilliant - well worth the extra money. It's very adjustable for pull, and does the whole rivet in one bite. I still make up a lot of electronics boxes, and rivets are great for fixing down transformers and fixing XLR (Cannon) sockets into chassis. This one does them nicely in one, controllable pass. For small work, I put the handle on the floor and push the work down onto it gently.
Three tips:
Strip and clean the collet jaws often with a wire brush, and use a fair bit of 3-in-1 oil in the collet. It won't stop it gripping, but it will help it release the pin - the handled ones need to do the grip-pull-release several times with standard length rivets, and if they pull too much each time and grip too hard they tend to jam, which is a right PITA.
Don't be wary of using washers on the back. It's often a bit of a fiddle to get them in place, but they make a huge difference to the strength of the finished joint, especially with thin steel and aluminium plate. The closer you can get them to the rivet diameter the better, placed so the sharp-edged side of the washer faces towards the plates you're joining (and the rivet gun).
Finally, if the finished look is important, pull on the riveter, away from the work, gently, as you do the last squeeze. That way, when the rivet parts, the pin won't bounce onto the surface, ruining any new paintwork. DAMHIK!
Pop rivets are so much easier than fiddling with small nuts and bolts. Have fun!
E.
PS: from good fastenings suppliers you can get steel or aluminium rivets. Steel do take quite a bit more effort for any given size, and I wouldn't attempt them with an ordinary hand riveter. If it's galvanized sheet, aluminium will probably be just fine, as long as it can't abrade when the door opens, etc. If you're fitting a strengthening plate around the lock, I'd fit a backing plate and bolt through both, as pop rivets won't withstand a crowbar (again don't ask!).