Hi Nick Pittari,
I am a relatively new member of Lifestyles Unlimited at the FFP (basic) level. The vendor list is pretty extensive, from what I've seen. For example, I used the insurance broker and got a better deal for my last property than I would have otherwise. The San Antonio/Austin office seems to have more vendors for San Antonio than Austin, but they seem to have both fairly well covered.
The benefits I see are networking, mentorship, classes, documents, and encouragement. Some of that you can get elsewhere, but I think it's easier to get mentoring this way than through soliciting strangers. I have seen/heard discussion of that fact mentioned here at BP (including BP podcasts).
So far, I've been able to ask a lot of questions both on the phone and at the meetings. It's nice that people seem to have a good amount of local knowledge and readily admit if they are not experts in some areas. While Lifestyles recommends a specific subset of REI focus areas, they have some members that vary that model.
The higher level memberships are supposed to do more of the work for you and help to pay for the greater time and attention you get from the mentors. They offer additional classes and perks not available at the basic level, though I don't have any direct experience with those levels, I have three friends who've joined and I haven't heard any complaints.
I hope this helps,
Dan