I own the Total Gym XL. I love it. Honestly, I think it's the single best piece of equipment out there. I've been a member of a few different gyms, and I was an athletic trainer (sports med, not strength & conditioning). I have experience with a ton of different equipment and types of equipment.
Total gym feels different than everything else. It would seem that weight towers with pulleys and handles in gyms would be the same thing, but they're not. It's hard to explain; you have to try it to know what I mean. It seemed awkward the first week or so I used it, but after I got used to it, I loved it.
The biggest benefit of it is core stability. You're forced to sit up during a lot of the exercises, thereby forcing your stabilizing muscles to work.
To be honest, I don't think there's a ton of differences between the models. The base you sit/lay on is probably it. Some are wider, longer, better cushioned, etc. There may be some that go up higher, thereby increasing resistance, but I don't think so.
I got one with a yoga kit (it was included for free). The only attachments I regularly used were the pull-up bar, and what was called the toe-up bar (or something like that). It was an odd shaped bar instead of the flat base. I used that for overhead press stuff.
I'd recommend a model that can add a weight bar so you can increase resistance if the highest setting isn't cutting it any more. Instead of adding weight, I made it harder by kneeling (weight and n my butt of completely on my knees, depending on the exercise)instead of sitting flat, kneeling on one knee, etc.
Other than the feel of the resistance, what I liked most was going from one exercise to the next, and on an on without a break. I got a great strength workout combined with a good cardio workout.
When I started using it, I dropped 40 pounds in about 3 months (with dieting). Then I got to the point where I wasn't losing weight on the scale, but my clothes were still getting bigger.
It's currently sitting in a closet. Kids, the dojo, and less space all added to that. Once I get my tenants to clear their garbage out of the basement, it'll be down there next to a heavy bag.
Also...
Call the company that makes it rather than the company that sells it. I think it's EFI or something like that. Find a number to customer support/parts/etc. and ask them about the differences and accessories. I did that because I was sick of the sales people's idiotness. After about 10 minutes, the guy told me they only make one model currently, and the other models are sold out. Order the cheapest one, and they'll ship you the XL without telling you. I don't know if that's still the case, but you never know. The XL was something like $700, and I paid about $300. If you keep asking about differences over and over and the guy gets sick of it, he may tell you the same thing. If you just order the cheapest one and expect to be upgraded, you might get burnt if they don't do that anymore.
I think it's EFI sports medicine that makes it (they have the total gym line and a rehab/therapy specific line). Another way to get them to give you an answer is if you start asking about putting the EFI accessories on the total gym.
