I've had good luck with teflon sliders on tile/concrete, but they do wear out eventually moving them around too. I bought these and been happy with them but don't move them a lot: http://www.marcospecialties.com/pinball-parts/LL25-EZG.

I've also seen posts where you can get Magic Sliders cups that fit over regular levelers on Amazon which would be easier to change as they wear out. I'm not sure the correct size so you'd have to measure, but something like these: http://www.amazon.com/Magic-Sliders-04600-Concave-Disc/dp/B000H5VNPY/ref=sr_1_16

Otherwise, pinball skates might be the way to go on concrete: https://pinside.com/pinball/forum/topic/pinball-skates-are-amazingwhat-took-me-so-long-to-buy-them

These are what I have and they are awesome. Even a widebody game slides like butter. Now, one of them did start to come loose, as in the the bottom part started to separate from the rest of the leg bolt, but I got some epoxy and now it seems very strong again.

Glad you started this thread though. I wouldn't mind trying some other options and having them onhand when in a pinch. I like them to help with pulling the games in and out to work on, not to make slide saves easier. My games are older and the tilts are really tight so that wouldn't work anyway.

Yeah, I really like them. I never had a problem with any coming loose, but have worn through the teflon layer on multiple sliders pushing them around the rough floor. I just replace them as needed, but if your floor is rough or you plan to slide them a lot it will happen.

Does anyone know where I can get some of the teflon sliders that were linked above? Unfortunately the marco link goes to a 404 now and I can't seem to find them on the site. Having the same problem here finding the right kind of sliders for games in my basement on the concrete. Thanks!