I think the big advantage MakeMKV has (apart from being a well-known and trusted app) is that the codes are being crowdsourced. Mike at MakeMKV simply asks users to provide dumps via an email address to any title that comes up as unsupported, and he seems to add them quickly to the supported list.
deUHD, on the other hand, has always been very closed and secretive about how their process works, and it’s a real mystery which titles may come out each week. Since they don’t appear to solicit input from their userbase, they are naturally going to fall behind into becoming obsolete.
And, unfortunately, their questionable support for the community through dishonorable business practices (limiting to 2 discs a day and not upgrading early adopters to their Pro tier) makes it easy for me to stop using their software, and recommend to new users not to bother with it, now that there’s a strong alternative with MakeMKV. They’ve already got my money, but it doesn’t mean they’re going to get a lot more—especially with their outrageously high price. They could charge whatever they wanted being the first game in town, but now that there’s a virtually-free alternative, they’re going to have to seriously rethink their offering if they want to stay in the market.
I use MakeMKV on my Mac, and still have deUHD on my Windows laptop, but like others, I haven’t even opened it in the weeks since MakeMKV support became active.