The best thing to do is read all the specs for each one, go look, and spend a few hours inside of the different models. Narrow you choices down, then test drive each one on highways, at highway speeds. After you have narrowed it down to two or three, spend a good amount of time getting the feeling of living in each one, then make your decision.
Search the archives here, you will find several days of reading material on both manufactures. It really is an individual choice, with both having their pluses, and minuses.
It'll be easier for folks to answer your question if you can specify which models, and new or used. With Chevy-, Ford-, and Sprinter-based models, you're probably asking too broad a question to get really specific answers. But I agree with Rodger, enter the brand names in the search box and commence reading.
Jim, "I plead contemporary insanity."
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory')
I'd add two thoughts to Rodger's (MyRoadtrek's) counsel.
First, when you "spend time" in a unit, be SURE it is without the sales rep and with your spouse/SO. You'll not be distracted by the sales rep, and the "time" spend will likely be several hours. For a few minutes, a "B" is fine. But, for several hours, well, you'll know.
Second, IMHO, selecting a "B" is a bit like choosing a spouse. You look around, look some more, and then look some more. And, then one day, it is crystal clear and you ask "the question". If you get it right - read, not in a hurry - life can be absolutely delightful. But, if you get it wrong, well ...
We looked for several years until the "aha moment" for our "B", and have never regretted it.
My bride and I can see our fiftieth on the horizon. Our "B", not so many years just yet.
Not to mention that Leisure Travel also makes a quality product - although they are expanding into the creative small C market. I moved up from a Great West B to a LTV C. They still make both a Sprinter and a Chevy based B:
See if there are similar sites for Pleasureway or others.
Take a weekend and go to an RV show that has several of the manufacturers there. At the PA RV show last year there was a Pleasureway group camping nearby. We stopped at the campground and several people were more than happy to talk about their B's. Ask them what they like AND dislike.
Talk to other owners.
We did all all the above and ultimately settled on a vehicle with the floorplan we liked best; that is the first priority. I knew I would have to do some mods, but I decided it was worth the extra work/$ because: it was the floorplan we wanted.
There have been a few surprises that I did not know about, and that has been frustrating. Still I would probably go with what I chose. One thing I would reevaluate is the diesel vs gas comparison.
Is there a reason you are asking about just these 2 manufacturers? I would consider checking out other B's as well and not limit yourself to just these two. I think most B manufacturers are good, but there are differences between them. I can only speak for the one we own which is a LTV and would definitely buy again.
X2 for Leisure Travel Van, also put together in nCanada. Can't think of any negatives after owning for a year and putting 7000+ miles on it. So keep them in mind along with others mentioned.
Re diesel...you'll find pros and cons on the boards. Ours gets 24 mpg but of course diesel fuel costs more. We're glad to have the diesel, others are fine with gassers. No single right answer except what works for you.
We looked around, pondered for two years for a low mileage good condition smaller RV and a used Leisure Free Spirit Sprinter popped up one day five miles from our house. I would buy another. Was also impressed by Pleasureway during the search phase.