Roller Disco's a widebody with double sets of flippers, with a mostly open playfield, so it lends itself to verrrrryy loooonnnng and slow ball play. Whether this is a blessing or a curse is a matter of taste. The scoring set is heavily loaded on bonus, although there's a long left side vari-target to collect bonus that allows for a progressive approach to scoring, as well as bonus carryover. It's relatively difficult to return a ball through the upper rollovers -- you have to get lucky off a top bounce from the pop bumpers - so being able to light A-B-C-D and get the two top star rollovers is a little quixotic. Not that it isn't a challenge, but it's more a matter of shoot the ball high and wide and hope for either a pop-up, or if lit, a roll down the mini-outlanes in the upper playfield in order to score specials. So the play is, well, OK.
As far as the theme, while there are some cute little squibs on the attract mode, the machine was just a bit too early to really capitalize on having Disco snippets incorporated, so it's a surprisingly quiet machine. Most of the shots do have semi-distinctive sound effects. But between the art work and the sounds, it's a lot less fun than the theme choice might suggest. (Oddly enough, the theme was too early to incorporate the kind of technology needed to emphasize the theme, and too late culturally to be cool.)
I may add this to my list of "ersatz licensed themes" - it may or may not have been meant to capitalize off the "Roller Disco Roller Boogie" movie of 1979, a year before its release.
As far as owning it, like any widebody, it's a labor of love for someone who has the space. (Disclaimer: I don't own one, but I help maintain one, sort of, for somebody who does...and who picked it up for the chore of moving it out of a garage, because they are BEARS to move even a few inches.)
One speculative note: certainly this is a game that will benefit MIGHTILY from an LED conversion and some add-on toys (like a flashing disco globe as a topper), and if it could be wired for sound with some appropriate songs, I can see making this into a major fun party pin. But it would require somebody with the proper motivation and creativity.