For me it outdid my expectations. I was hoping for just a nice personal content machine, to give me back the great portable experience I had many moons ago with a 12" G4 PowerBook, with no ambitious uses in mind.. since those days my only really truly portable platform has been the iPad (only ever bought 17" laptops as desktop replacements since the 12" PowerBook), and while the iPad is good for some things, a laptop it isn't.
Instead though, it so far has turned out to be a real and absolutely all-round computer in every way. It feels so normal to use, so zippy and effortless at every day tasks that it fools me most of the time that I could just use it as a main computer. I know that this isn't the case because it would not cut it for my real work in Logic Pro. But what's crazy is that when I'm using it for browsing, watching stuff, emailing, listening to music, working on my website, editing photos etc.. it really does not at all feel like a painful slowpoke coming from the much more powerful iMacs we use for real work. The general experience of using it (interface speed, app launching, boot up times etc) all feels absolutely contemporary. And even though I knew I was going for this machine for a super-portable experience, even that part of it I underestimated. Turns out that actually owning one and discovering just how effortless it is to carry it around, and yet feeling like you have a full machine with you, is better than I imagined. I'm discovering times and places that I just would normally not be bothered to go to all the trouble of getting out a computer to do something, now it's just second nature. Used to hate the rigmarole of pulling out the laptop on a train (even if I had someone's 15 or 13 inch MBP with me), now it's just the definition of no big deal.
On top of this, the display and built in speakers are just so unexpectedly better than I could have thought, the thing is just a pure pleasure to use for kicking back and watching a movie. And the no fan thing - for a workhorse machine I'm still totally fine with fan noise, I think that's going to be a necessary evil for a while. But for a personal companion machine like the rMB, it feels downright civilised that it doesn't subject you to any of that. Again, something I underestimated the value of till I got used to it. Every single friend I know who uses a laptop for non heavy crunching work who has seen mine so far - after a few minutes getting their heads around it, I see a switch go off in their head saying "OK, this is what I'm getting next". It's hard to put into words how compelling a package it is - it's one of the most well realised fit-for-purpose machines I've come across in a long time. Of course if you need more than what it offers, you realise pretty quickly it's not for you. For me it fits a gap perfectly next to the bigger machines we use for work, so it's place is well defined. I guess what I'm saying is that it's just a really excellent expression of an ultralight laptop, and it lives up to that role in an extremely well-rounded and fulfilling way. It's really just up to you to know whether a machine fit for this role is what you need or not.