...late to the party, as always. My 2 cents:
I have personally seen Hallmark, Outfitter, Northstar and Fourwheel campers.
All of them make a good product with somewhat different strenghts and weaknesses.
Our Outfitter is unique in that it has an aluminum frame, a basement, a one-piece fibreglass roof, a full wet bath, and north-south bed - all in the same camper. We have had the camper for 4 years now, it has been quite rugged and dependable, but the build quality was not overwhelming. We are still very happy with what we got for the money.
Hallmark campers are similar (both companies are actually run by relatives) and seemed to have a higher build quality.
Fourwheel campers are comparatively basic, but extemely robust, dependable and durable.
Northstar makes a very attractive product built the traditional way. I would not hesitate to buy one.
You need to clarify - for yourself - what you want to do with that camper. How many people will travel, what do they take with them, where do they want to go, at what time of the year, ...And why you want a popup vs. hardside. We have found the only real downside of the popup was the fact that you can not stealth camp in one.