Exhale.
For starters consider how you intend to use it.
Boondocking? RV park with full hookups? Weekends mostly, or longer stays?
Longer stays, more dry camping means you need bigger tanks.
5800 and 6500 lbs are dry weights. With a half tank of water, propane and tanks, and a battery, (still no clothes dishes etc) You will be 6500 - 7000 lbs, with a 1000 lb tongue weight if you properly distribute the weight. Add the necessities and your probably between 7500 and 8000 lbs, is that the weight range you were looking for?
As to quality, you are about right, all are entry level, the Jayco could be either metal or glass sided, the other two are metal.
Appliances, equipment will be near identical, so look to fit and finish to distinguish the differences.
Pressboard is the cheapest cabinet and drawer material, plywood is better, hardwood is better still.
Staples are the fastest and weakest fasteners, brads are a little better, and screws are better still.
Pick the one that feels right to you and that fits your needs.
Then search online through
RV traderand
rvt.comusing their advanced search, look up the exact model you want, and see how the prices vary.
Go to the dealers websites, and look for their terms. Some advertise low prices and then add thousands in hidden fees as well as trying to force you to use their preferred lenders. Others will price their product straight up, out the door. Make sure you are comparing apples to apples.
Good luck