A good clue to the overall "quality" of any Japanese steel bike of the 1987 to 1989 period is the "group" used. In 1987, Shimano released the "Shimano 105" group with improved indexed shifting and the spectacular SLR brakes (NOT available on 1987 Dura-Ace). So, I'd buy ANY bike with Tange or Isiwata tubing that had the 105 group from 1987, 1988, or 1989. The Dura-Ace and Ultegra 600 groups for 1987 and 1988 were very nice, but lacked the SLR brakes. In 1989, those groups were "upgraded" to match 105. Then STI came along, and shifting and braking quality took a major hit.

I've loaned several friends one of my late '80's bikes with Japanese tubes and SLR braking. They are usually rather surprised. The braking and shifting have superior feel and precision when compared with the components on $1,000 bikes made in 2005. The ride quality and handling are generally superior to any production bikes of 2005, matched only by custom steel frames, from companies such as Rivendell.

So, a 1987 Centurion, or Panasonic, or Bridgestone with Shimano 105 can give you as good or better a riding experience than most of the bikes up at your corner LBS...but for $200 or so, not $1,000 or $2,000.