I've had both the TomCat and Keltec. I've shot a 1907 Savage that belongs to my father-in-law a bit also.
I only experieced rim-lock once. It was because I intentionally loaded it with the rim over the one lower while loading the magazine to see if it would still feed. It didn't. (It was with the TomCAT that I tried it with).
I never much thought about it until I started seeing it mentioned on the internet. Ditto with the .38Super that shares the same "semi-rimmed" design.
I've never heard of any of the guys I've shot in competion with and against say anything about it with the .38Super. I quit shooting the Super when I got a S&W Perf.Ctr 9mm and haven't thought about it since.
If you will pay a little attention to the loading process I don't think you'll have a problem. Just realize that if you happen to get the rim of one cartridge over and behind another, It won't "strip" or feed itself. It'll just jam...
I never experenced it myself other than intentionally inducing it.
I've heard of it often, but I think it's mostly operator error. Although I suppose that anything is possible......
re: the TomCat.....
I really, really liked mine. It was very-very accurate, not just for a pocket pistol. It'd shoot ~2.5" groups to POA-POI at 25yds. However, I shot it to death. Literally.
After about 3,000rds (guesstimated, I shot it regularily for several years while I was carrying it as a back-up while employed in L.E.). Most loads were "american" factory equivalent with a 78gr bullet I cast over 1.6gr of Bullseye. However, I too shot a good bit of Fiocchi 60gr HP and eqivalent loadings (reloads) of both 60gr XTP's and Speer GoldDots duplicating the VERY HOT Fiocchi loading (1,050fps from the 2.125" TomCat). The frame and slide cracked. I sent it back to Berreta and they sent me another one...... FREE !
I traded it off "NIB" for something else.
I gave my Keltec to my brother. He carrys it as a back up on his job.
Either will give the average shooter decent service, but they aren't designed or built for heavy long term use like a S&W mod10 revolver or a Glock or similar mil.spec duty weapon. Kinda like an older S&W mod36 with +P, they'll shoot loose and break eventually.