Hi Pitt1953. We've never owned a Fleetwood product, but they've been around for a long time (in RV years.) The Discovery has a good name, and since it's a 2015, I would guess that most, if not all, the new RV problems have been resolved by now.
Having said that, my recommendation would be to test every appliance and system before dropping a dime on it. For example, don't just make sure the generator starts and runs, test it under a load for 20- 30 minutes. Unplug from shore power and make sure all the 12 volt systems work, including the inverter. Run all the appliances and open all the cabinets. The appliances will be common appliances that are found in a lot of RVs.
When we were last shopping for RVs, we looked at a 2014, 40 foot Discovery that a friend had just purchased new (I think it was a 40E.) He told us that, after running the large slide in and out a few times, one of the floor tiles cracked. After getting it repaired under warranty, which took two months, it happened again. Apparently it was a common problem to that model, so you might want to look closely at the tile floors. Good luck!
Kev