I have Inde BR2's on my toms as tom mounts. I notice an increase in sustain (and the ability to "tune" the response of the mount is not just a gimmick) but having the ability to use 9, 10, or 12mm L-arms is really important to me since I have a lot of different stands and clamps and the industry has left the vintage 9.5mm arm far behind.
I like the idea of Atlas mounts and if I had undrilled drums I'd probably consider them, but they're bulky and don't work with 9 or 10mm arms, and would leave open holes.
I'm very impressed with the style and function of the Inde mounts and I think they're a great upgrade.