Hi all, long time lurker but I took the exam today and this thread was pretty useful for my prep (even if highly stress-inducing with all the 260+ and whatnot...) so I thought I'd share how it went/what I did to prepare.
Prep: Went through Kaplan QBank sort of halfheartedly during coursework (my general thoughts are that it is more random-detail-oriented vs. thinking-oriented, but didn't have enough detail for our block exams so I stopped using it. The questions also always felt like they were trying to trick me, which is a terrible mindset to get into for real board questions). 4 weeks of serious prep after classes ended (2 blocks of UWorld each day, review + 1 FA chapter with at least 2-3 hours a day spent reviewing missed questions/memorization), probably 12-14 hours/day studying.
UWorld was probably my best resource, FA was great for getting facts but very concepts from FA showed up on the exam directly. Also tried to get through 2-3 chapters of Step 1 Secrets each day (which I highly recommend, it's an easy read, helps nail down concepts, and is good about cross-referencing material from different organ systems). Between these three sources I felt pretty well covered and would use WebPath for systems-based path review after doing the relevant chapter in FA.
Practice Scores:
4 weeks out: UWSA1: 222, NBME11:233
3 weeks out: UWSA2: 247
1 week out: NBME15: 257
3 days out: NBME13: 259
2 days out: Free 150: 93%
UWorld percent: last week was 78%, started at 63% and finished with 74% overall. I would NOT recommend using UWorld as anything other than a learning tool, the percentages are very difficult to interpret and most med students are neurotic enough (present company included) to make worrying about yet another number just more anxiety than it's worth.
The actual test was... not so great. Very few questions were directly from First Aid (and I whiffed on 4 of those), but I felt that I had seen questions similar to the material before in UWorld or on the NBMEs. Maybe I got a difficult set of blocks, but most questions required at least 2 steps of reasoning and most required >=3(!) - e.g. ID the organism from an image, recognize the best treatment for the organism, answer with the mechanism for that treatment. Lots of questions that weren't straight recall - graph interpretation, arrows, that sort of thing.
Walked out feeling like it didn't go so well and will be thrilled with anything >230 (stupidly, I looked up the ones I was unsure about in agonizing detail and am pretty confident about missing at least 20... but I'm also not sure that the curve is as strict as SDN lore would have one believe, so idk). The next few weeks I'll just distract myself so I don't have to think about it. 🙂
By subject, I felt that micro, biostat, and pharm were underrepresented (probably only 2-3 each of micro and pharm per block and <1 biostat per block), while neuro was well-represented along with embyro (got some very tough ones that I pretty much had to make an educated guess on). Phys and path (esp. for respiratory and renal) were big time. I only had 1 two-part question and two audio, both of which you didn't really need the audio to figure out. Some blocks definitely felt harder than others, so don't panic if that happens to you.
All in all, I felt that my prep time was adequate (most of the FA whiffs were due to second-guessing myself). Trust your gut! And take breaks, those help tremendously in getting refocused and ready for the next block, even if you just leave the center to walk around for a bit. Take the day before the exam off - if you haven't learned it by then, it's not going to stick, and relaxing will help you more with the test than cramming a few more factoids.
Good luck to everyone who hasn't taken it yet!
Cheers to 2013 
