I picked up a Pasco 4661 compression sleeve puller from my local plumbers supply, stock photo below. I am redoing my bathroom and wanted to put in new valves and escutcheons on the wall but had no way to get the damn compression ring off. I just tried on my garage sink and I love this thing! Thought I was going to have to cut the rings off but was afraid of cutting into the pipe but this thing made it so much easier as it took less than 15 seconds to get the ring off.
On a side note, I can only use this thing so many times so I was thinking about setting doing a thread where I loan this thing out for free like Autozone does with their tools. Someone would send me a deposit, I send them the tool and when I get it back I refund the full deposit. Hopefully this way someone can get use out of it as when I am done this will have a lot of shelf time in the garage.