If possible, I always prefer to see a game's original artwork be preserved as much as possible: Clean it, repair damaged wood, touch up scuffs (particularly easy when the artwork is mostly black as on Space Invaders), and make everything function perfectly. Stripping off the old paint and redoing the artwork can result in a great looking "time capsule" game, but it is a LOT of work, and really seems more like some twisted kind of vanity than a loving restoration. Let the game keep a few of its battle-scars!