The '86 through '88 are similar to the '89's. At this point, their prices are all about the same.
I have an '86 Marquis is how I know; had it since, um, '92 or '93? I forget.
Anyway, a large amount of goodies and construction technologies were pioneered by Beaver in that time frame and the better coaches use them now.
The Gillig chassis give me mixed feelings. It's rock solid but you have to watch the (numerous) rubber bushings in the front end as they wear out about every 10 years or so. (Who'da thunk?)
They are not expensive to replace and most are easy to install.
Of course, the cabinetry and woodwork are to die for and nothing, I mean nothing exists like it in the RV (or most boats) industry today.
Some fool backed her SUB into the side of the Beaver in a gas station a while back. Buckled the rear end of her SUV and shattered all her rear glass. Not a scratch on the Beaver.
Mine has the 3208T, set at 250 hp. I get about 8 mpg and without a toad climb all but the steepest hills just fine. However, with a toad, on steep hills you slow down as much as the 18 wheelers do.
The coach only feels crosswinds of 40+ mph. Big 18 wheelers passing us make no difference to the drive. I usually keep cruise set on 65 on the freeways and 72 if I'm in a big hurry.
Every appliance and fixture in the coach was the very best available at the time, and bests some of today's. Others, not so much -- like TV's, for example.
The only reason I'm looking for a newer coach is because "I must have slideouts, slideouts, slideouts......"