Being the only person on the planet who has owned both an XVJP and an AT Habitat , I can provide some perspective on entry and interior space and a few initial thoughts.
The Habitat is clearly designed to augment a stock vehicle, and as such, the price is 5% of an EarthRoamer conversion (which can only be purchased one way). No doubt the XVJP is easier to enter, although my JP had a terrible rear bumper that had to be swung-out first before opening the rear door. An AEV bumper would solve that.
The EarthRoamer also feels more like a camper- because it is. The Habitat is more simple and robust, and still allows five passengers. The EarthRoamer has many integrated systems and reflects Bill's uncanny ability of making something small seem big inside. I lived in my XVJP for three months straight and never felt the design to be laking (considering the platform). The EarthRoamer JP is a unique and extremely niche (and expensive) product. I was owner #6.
With the Habitat up, the space inside is massive. It is so big, you could put a table and two chairs in the space above the driver passenger and have a tea party. You can also sleep 4-6 comfortably in the Habitat, and the Habitat can be configured to sleep 1-2 with the top closed. That is one of my expectations of a pop-top- you must be able to sleep in the vehicle with it closed-up (weather, security, etc.)
There are a few things I really like about the Habitat design.
1. Simple, Strong and Light
2. A la carte approach, from just the top to a full camper design (which can be done by the owner or AT)
3. Vehicle can be returned to stock and a new Jeep can be purchased. Have a 2007 and plan to upgrade to a 2012 for the new V6? No problem.
4. No change to the vehicle warranty and limited change to its ride/drive/functionality.
5. Incredible bargain IMO. $6,000 for a top, which is less than the factory top option, a rack and RTT - amazing.