You might have a better chance selling it if you can show anything that has been done to fix the bugs. For example, has the hulk saucer drop been addressed (many times the ball will drop and fall out of the saucer), the loki screw where the ball sometimes gets stuck needs a patch, does the ball get stuck under hulks arms, etc. I think the machine is worth more than 3500 if you can show its bug free. Adding LEDs really makes this machine pop.
That said, For prospective buyers, most of these fixes are available from stern for free and it takes only minutes to fix. People harp on quality for this title, but I've had mine since January, play it all the time, and not a single thing has broken.
I paid a lot more than 3500 and consider this a steal. If I didn't own one...