I own an H2, and I strongly suggest them as middle ground between a PC and an (SBC) ARM. One of the main advantages is support, both in terms of applications (some programs may not yet compile on ARM), and kernel (although (some) ARM SBC can run with a stock kernel, it's advices to run a specific kernel to run optimally). The H2 also run impressively cool, and I suppose the H3 does, as well.

Note though, that RPis have never been the most price effective ARM solution, as Hardkernel has always had more powerful and/or cheaper alternatives. Their current N2+ is probably both more powerful and cheaper than the equivalent RPi.