I'm pretty sure that the reason the Edirol lacks 48khz is because it's not at all intended for any kind of "pro" market, much less tapers. It's more intended for musicians and the general home studio buyer. Which probably explains why it's so user-friendly.
I'm guessing the 24bit inclusion is because most things are running or promoting 24 bit these days, especially Edirol products, whereas the average consumer isn't really looking at anything higher than 44.1khz (not to mention most probably don't even know what that means, besides the phrase "Cd quality"). In this day and age of mp3s, I think plenty of people are only becoming somewhat more aware of bitrates and how they affect the quality of the sound. But apart from audiophiles and pro video/audio guys, I think 48khz is a ways off from being the mainstream (dvd-a is just beginning to takeoff). Not to mention that it seems to have been overshadowed by the 96khz bug everyone seems to have, which I think is simply because everyone now has the idea of it being "the best". Not too long ago 24 bit was "the best", but now that goal has already been achieved, we've all pretty much forgotten it.
For anyone who's been going over this whole MT vs. R-1 vs. Marantz thing, don't lose track of how far this technology has come and how much farther it will likely be going: Something better will be coming along just around the corner. Unlike the Sony DATs or the MDs, this technology has SO much more potential. Not just from a size perspective, but from a quality perspective. Whereas Tascam and Sony were the original makers of some of the most common units back in the day, today we have Edirol (Roland), M-Audio, Digidesign, Grace, and tons of other "new guys" who have yet to even step up to the plate with their own products. This technology will just keep getting better and better. As for now, I think I find it premature to blow $400 on a product that doesn't work. Why not save the money and wait 9 months for the next piece of gear to come along, or instead buy a product that works.
My current thought is that the price of these things is only going to stay so low for so long. Now that the R-1 and MT have started at the $400 range, I'm not so sure we'll be seeing too many more recorders at this price point. I assume that they can only go up from here. We already know the Sonosax is going to be priced outrageous, but I'm betting you're going to start seeing the development of palm-sized multitrack recorders with way more features and much higher quality design. Perhaps we might find out in the future that these current recorders were as cheap as they're gonna get.