Given these two options, the REI tent would be the clear winner for me. Here's why:

1) The REI tent is free standing, while the Nammatj 2GT isn't. I find that free standing tents are generally faster and easier to pitch plus they give you more placement options than non-free standing tents. I've camped in places where the ground was so hard it was impossible to get a tent peg into the ground! Nice to be able to erect the tent, then move it around... or open the door, hold it vertically, and shake all the dirt out of it Having used both types of tents, I would never buy a tent that wasn't free standing

2) The MSRP of the REI tent is significantly less than that of the Nammatj... especially if you wait for one of REI's 20% off sales

3) The REI tent has a lot more floor area than the Nammatj. The flip side of this is that the Nammatj has quite a bit more vestibule area. You'll have to decide which is more important to you. I tend not to use much vestibule space. Bugs and varmints can get into the vestibule and the ground can get pretty swampy when it rains. I might leave a muddy pair of shoes in the vestibule, but tend to keep most other items inside the tent.