We have a 99 GB Landau and love it.
Have someone (other than the seller) check over the mechanical, structural and systems for immediate issues - if you are happy with the floor plan go for it.
When we bought ours we read on several forums where people were beating up GBs but from what we have seen it was unwarranted. The sames systems are on all RVs, the same type chassis are on many RVs. The important thing on an older coach is how well kept it is. If it needs something big replaced or repaired (AC, Tires (age), roof, etc) make sure the price reflects it.
Coachmen ended up with the GB "stuff" and calling their service support will help a great deal with any issues you stumble across.