Heh, I just bought a new PC from Dell, and had to jump through all sorts of hoops to make sure it came with XP and NOT Vista, LOL! I knew better...
Anyway, I'm going to add my opinion and go against the grain here (at the risk of being ridiculed).
For starters, to me, this decision comes down to two factors: 2 vs. 4 channels and more vs. less bulky. So think hard about those two things, and you'll have your answer.
FWIW, I've been running a stock R4 for a year and a half now, and I love it. I've never had the HDD slow error, and I've been completely satisfied with the sound quality. The ability to matrix so easily, and to mix in post, is simply spectacular (I bring 4 XLR cables and a pair of 1' XLR-to-1/4" adapters, and I can patch 95% of SBDs). And, the ability to run an AUD pair plus two more channels can also be very rewarding -- whether you run two stereo pairs or one pair and some spot mics. Your options are many. Also, contrary to what some may say, I actually love the gain staging the way it is, between line/mic-in and my pads on my mics, with experience, I can handle almost any scenario from super quiet acoustic (mic-in with +6 db on my 480s) to extremely loud and bassy (line-in with 10 db pad on the 480s). The thing is an absolute workhorse, and seemingly runs forever on a standard walmart dvd battery (I've done 6+ hours of 4-channel with phantom on all four with the LCD on the whole time with battery to spare).
The two downsides are BULK, the thing is kind of big no doubt, and if you're picky, maybe sound quality. I've got a crapload of MP3 samples readily available on my website (see sig) if you want to quickly listen to some stock R4 action, some with C4s, some with 390s, some with 480s, and a bunch of 4-channel mixes (AUD+SBD, 2xAUD, and AUD + 1 or 2 spots).
Good luck, I don't think you can go wrong either way really...