I'm quite a big BTTF fan myself
For a 1988 era pinball machine I'd say it seems like an above average machine for it's time. However when compared to more modern machines it's really dated. The playfield is really simple and while it does have some cool soundbites the audio is all midi which a real bummer IMO... but that's more a limitation of the technology at the time of it's manufacture than anything else. The playfield is also really simple which I don't really care for personally.
Usually what I look for in a pinball machine is if you took away the playfield graphics and the sound is the game still interesting? and does the game still give you a feeling of the theme from the playfield features? The answer to these questions I think is sadly no and no... take away the images and sound and it's just a couple of ramps and bumpers, nothing BTTF about it left and nothing particularly unique about it either. Also it looks like Michael J Fox didn't license his likeness for the machine which is a real bummer too and takes away from the graphics that it does have (at least Christopher Lloyd is there)
Nostalgia is a huge part of what drives collectors of Pinball and Video arcade machines though.
The good news is that since it's not on any best-of lists you should have an easier time finding one for sale, and wont pay as much if and when you find one
