My take on it is they are both niche products. Both cost more than other trailer brands. You have to decide if the cost difference between these two brands, and the others is worth it to "you".
Neither provide a great bang for the buck compared to others.
Spend some time on both the Lance and Airforum. Read about the good bad and problems areas of both these, and you may conclude they have more in common with other brands than you might otherwise assume.
I considered and looked at both when I was shopping. I declined on both for a variety of reasons. Your reasons may ( and probably will ) vary.