We also owned and loved a 2007 Leisure Free Spirit 210B. (Would still be using it but a large Labrador service dog joined the family, and we needed more room for her to sleep somewhere without worrying about stepping on her in the dark.) We traded it in last year and got a much higher than expected trade-in value for it.
All the brands you mentioned made/make quality products. I don't think you'll go wrong with any of them.
One thing to know, if you don't already, when shopping used diesel models is that a T1N generation Sprinter (up until about the year 2006) on a 2500 chassis can easily get between 18 and 25 mpg. After about 50,000 miles, ours started getting 25 most of the time. We had a Freightliner badge on the grill, others had Dodge, others might have had a Mercedes badge. Regardless, they were all Mercedes products marketed in the US.
We put about 10,000 miles on it every year and really saw a lot of the U.S. And Canada, staying one to five nights in each place. The set-up and departure time was very minimal (usually just plugging in/unplugging the power cord if in a campground with electricity). That made it so easy to run around sightseeing, go somewhere to eat, buy groceries, etc. without the need for a second vehicle. And parking was easy just about anywhere except garages with low ceilings. Very easy to fit into campsites.
Another thing to look for IMHO is a three-way fridge. 120 when you are plugged into a campsite, 12 volt while driving, and gas (propane) when you stop for sightseeing or don't have hookups. Doesn't use much gas. We had a propane generator, too, which was handy.
Layout is a personal choice, but I liked the open feeling of our model, with high cabinets all around so I could be sitting in bed at the back and see straight through the windshield in the front. It had the bathroom behind the drivers' seat, and the galley on the passenger side. I've seen some Bs that had low-hanging cabinets that made me a little claustrophobic.
I'd buy another B in a heartbeat.
