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

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.