I’ve had around 20 sessions with a Q switch laser on my leg tattoo which was black and grey. Lighter parts of the tattoo have almost completely gone however the larger, darker parts have scarred and look similar to a large bruise.
My advice would be to use a q switch laser for as long as possible as it’s much cheaper. Then once it gets to the point where it plateaus go to somebody with a Ruby laser. Personally though I think it’s better to get the tattoo covered after you’ve removed a decent amount as the scarring can leave your skin very dry all the time and looking a bit of a mess.