I do not know anything about Biesse equipment, but we did buy a used Brandt Optimat 76 in 2012. This machine was a 2002 model. We did have a lot of problems getting it to work properly, but it works great now. It does not have corner rounding or pre-milling.
The edgebander had set for a couple of years, and when we got it wired, we could not get it to turn on. The battery in the computer control panel had failed and we had to bring in a technician to get it going and to reprogram it.
A couple of years ago, the computer in the control panel went out and this is old technology for computers. It was going to cost us $3,000 for a replacement from Stiles, and it would have to come from Germany. Fortunately, I have an employee that knows a lot about computers and he was able to take parts from an old computer we had and make it work. Then, the monitor went out, again my guy was able to take an old monitor and make it work.
This year, we had to replace the bearings for the glue pot and we are careful that we clean up any over flow of glue after we shut it down.
On the positive, I only paid $13,000 for it and we run a lot of 5mm solid wood edging and it does a good job at putting this on. Running just edge tape, it is about as good as I could imagine. For solid wood, I feel you need a heavy machine.
My opinion is that you should expect to have to make repairs and if these machines are older, 10 years or more, their computers may be out dated and it take a talented person to repair them. But, my Optimat sold new for over $70,000.
Good luck