I'm one of the "instructors" for the ULBC course (as well as other WTS courses and the WTS Manager), so what I say may or may not count for much. :-)
The ULBC course was something Ryan developed somewhat outside of BPL with the help of myself and a few other members of the UL community. The virtual portion is divided in to modules (hydration, nutrition, packing, clothing, etc.) and you spend some time on each. The materials are mostly PDFs and videos unless you choose to do the mentored and/or trek options. With the mentoring, Ryan will communicate with you directly in regards to your gear choices, etc. The trek is more or less self-explanatory. If you're new to BPL or lightweight backpacking in general, the ULBC materials *should* help you pick up all of the ins and outs at an accelerated pace compared to searching out everything yourself. If you're more experienced, I doubt you'd learn a whole lot from the materials. The trek is a worthwhile investment (treat it like a learning vacation) either way, IMO.
Last year was the first time we've offered the ULBC program and there were definitely some kinks with the virtual portion that we *hopefully* won't experience this year.
The trek itself was excellent and we got nothing but positive feedback on that. Josh Levitt of Ruta Locura (formerly of Titanium Goat) and myself managed to hike something like 24 miles in 2 days while only covering 8 miles of trail. Long story short, we had to evac one of the other guests/students due to some physical ailments on day 2 and catch up on day 3. The rest of the group took advantage of a late break from camp (while waiting for us) by fishing Tenkara style in the alpine lakes. If you've never been in the Rockies, the trek is a great way to experience it without having to do any planning yourself.