I've been using one for the past ten years. I don't know how I got along without it! They can restore/repair usually 8 out of ten picture tubes. The B & K models 467, 470, 480, and 490a are excellent older units and use the "CR-xx" series socket adapters. The 490B is the current model and sells for $1,100. The Sencore CR-7000 restorer sells for $2,100 while it's older brother the CR-70 sells on the used market for $1,000. All brands of rejuvenators use socket adapters to plug onto the back of the picture tube so you need to look in the chart supplied with your model to look up which adapter you need to test/restore your particular tube. On the B&K brand units adapter CR-23 covers most video arcade monitor tubes used in Electrohome, Nintendo Sanyo, and Wells-Gardner. Adapters are an accessory and typically cost $50 to $65 each.
Most tv repair shops charge around $50 to rejuvenate a tube. If you have a lot of games or buy/sell/repair games then this is an excellent investment. Be sure to also buy a "high voltage probe" seperately to discharge the monitor before using a rejuvenator or the rejuvenator will be damaged!