Well, I'm back. My impressions, in no particular order:

1) The hard product is excellent. I managed to get 5.5 solid hours of sleep on the outbound -- some of the best sleep I've ever had on an airplane. The seats are considerably roomier than the AC J pods, they're more comfortable, and lying flat doesn't provoke that funny head-down feeling the AC J pods do. IFE is pretty good, too; AC flyers will appreciate it when I say the system only crashed once on me, and that was before pushback on the outbound.

2) The soft product was... odd. My wife found the service on the outbound to be perfunctory and dismissive; I think I'd call it "efficient," in that everything showed up more or less exactly at the time it was supposed to, but the flourish that one might have expected was lacking. That certainly wasn't the case on the return; purser Eric introduced himself to everyone in the F cabin, left business cards for everyone, and made it abundantly clear who his priorities were. I've had this kind of service on AC as well, but UA seemed better in some intangible way. As EnvoyBoy notes upthread, it feels somewhat hit or miss -- but the hit was a home run all around.

3) Food: I'll post the relevant details in the appropriate thread, but I can safely say that was some of the best filet mignon I've had anywhere, and the miso glazed sea bass on the inbound was really excellent. My wife says she thinks the AC food is better; I think UA has the edge on this one.

Conclusion: I'm not sure that, given the option to spend the points (or the money, for that matter) on UA F over another carrier's F product, I'd do it again; I'd certainly be more interested in trying, say, NH/OZ/TG based on my expected flying patterns over the next year or so. But I was happy, comfortable, felt well taken care of, and really I have no complaints about how anything went. In fact, I'm so pleased I'm sending e-mail to UA to compliment the various crews and station staff, and that's a bit of a rarity. In an industry where I often feel like handing out C+ or B- grades, it's rather nice to be able to talk about a solid "A" rating.

We also managed to come home with ten (!) amenity kits between the two of us, so that's a new one for me, too.