I've been taking a hard look at Haswell systems, especially the ASUS MOBOs, to see how they compare to my present build (which I'm not replacing—I've too much money tied up in it—but I was curious to see if I was wise to go ahead and build when I did instead of waiting). The X87 Deluxe Dual, X87 WS, and X87 Deluxe, in that order, especially caught my attention. They could meet my needs, albeit barely, but I have concerns about the CPU itself.
Intel is using a TIM between the chip and the heat spreader, like they did with the Ivy Bridges, instead of soldering, like the Sandy Bridge-E and earlier. The Ivy Bridge CPUs have had problems with the chips overheating due to poor heat transfer from the chip to the heat spreader, resulting in many owners delidding them so the TIM can be replaced. The new Haswell CPUs are also not soldered and there already has been a handful of early user reports about them running hot.
I don't regret going with an X79 build instead of waiting for the Z87s. I needed a new desktop back when I built mine. I would have had to wait at least five months for the Haswells (my two top choices still aren't available yet) and it's always fiscally wise to not be a first adopter of anything since the first runs are usually buggy so I would have wound up waiting a year and wound up with a system that wouldn't have been much better than what I have now (albeit less expensive, though). Still, it's interesting to see what is, and is going to be, out there.