I finally tried mod-DH today; I've spent roughly 6 hours using it and got from 10 to 100wpm on TyperA and 124 on 10ff! This was the fastest I've ever improved at something. I'm proud of my learning pace. However, I've already noticed a few roadblocks.
My biggest issue is the bottom row for the left index finger, which isn't unique to mod-DH, but it's more noticeable now. On ANSI layout, my left index is forced into having to take care of 3 keys, D, V, and Z, causing me to occasionally miss when typing fast due to the different distances. I'd prefer putting some of that stress to my pinkie finger without having to resort to using the shift key as Z. Another issue is that I used to angle cheat, so I have to relearn more keys and bigrams than the average user switching from vanilla. Because everything else is the same, my brain randomly gets confused and starts thinking in vanilla instead; when I switched from qwerty to Colemak, I changed my typing technique as well, which gave me a clean start. Believe me or not, this switch so far was more frustrating than qwerty to Colemak.
I believe I'm missing a lot of DH's potential by not having a matrix keyboard, but even then, plenty of words on TyperA feel significantly easier while just a few are harder. As difficult as it is, I'm having fun. I think the effort will definitely be worth it! My finger tendons and wrists hurt quite badly after the practice today. I need to tame my lust for improvement :D