H2H and H5 have effectively the same CPU. It's just that the CPU in the H5 has hardware support for 4K included (that doesn't mean it'll work for 4K via VM though). Everything else about the CPUs are the same. You might be able to get 4K through IPTV (I don't know for certain as I don't go near IPTV) - in which case you might want the H5. If not, stick with the H2H - it's got the same amount of grunt as the H5.
Although, grog68 has also mentioned the H5.2TC. This is effectively an H5 with a dual cable tuner. If you want to watch one cable channel whilst recording another this is definitely the box to get.