When you stop and idle, you're gonna feel it. It shakes everything inside. The blurry mirror was a bit annoying till it fell off. Basically, everything vibrates. The other problem with this is that the exhaust will also vibrate. I think this is what really killed two exhaust mounts and tore a hole in the pipe near another mount. If you're jeep isn't a daily driver then it might not be that annoying but as a daily driver, I'd stick with stock mounts. Not to mention, I can get a complete set of 3 mounts for $35. I do have JKS 1" pucks.
I used to have a 1" Poly Currie MM and a TD 1" Poly mount. The upside to it all is that the engine doesn't rock when you jump on the throttle so you end up wasting less energy torquing the engine.