I'd say that they are similar for the most part, but one important factor in my mind is that the Liberty comes from the factory with less ground clearance than an Xterra. It's not a lot of difference, but sometimes just a small increase is the difference between clearing things and banging around on them. I don't know how the Liberty skids compare, but I doubt they are anything special either. I've never wheeled a Liberty, so that's as far as I can go.

On the road, the Xterra has a more comfortable ride than the Liberty, and the interior is more roomy and comfortable, IMO. The Liberty doesn't have much shoulder room so unless you're toothpick thin you may not like it. I also prefer the more "legs out" driving position of the Xterra, but I may be in the minority there and that may not matter to you. The Liberty does offer better acceleration performance, being lighter weight and having more power.

Without question, the Xterra has more room for carrying your wheeling/camping gear, and I believe it has a higher tow rating...things to consider. That "kicked in the ass" look of the Liberty really eats up cargo room.

Although any vehicle can be problematic, I think the Xterra is a better bet in that department.