Right now I do not care about my wpm, it's at least as fast as I can think.
What I do care about is the ergonomics and the customizability, where the Ergodox Ez excels. I don't ever need to stretch out far or in any weird way anymore. Heck, most of the time I don't need to stretch out for my mouse anymore.
I've had an Ez for years and I'm typing this on my brand new Moonlander. I think it's nice, but I don't think it's that much of an upgrade over the Ez. The new thumb cluster is a bit better than the EZ IMO, but it's not a complete win because of the hinge that creates a pretty wide gap between the main board and the thumb cluster.
I don't regret my purchase but if I were you I'd wait for something a bit more consequential, maybe a Moonlander Mk2. Or a more drastically different keyboard, like a manuform or a kyria for instance.
I was going to buy an EZ myself but went with the Moonlander because of the smaller size as it felt counter productive to have a split keyboard for ergonomics but have my hands hurt because they keep stretching to reach the thumb cluster.
I just learned about this last night, and was really considering it. One thing that I wasn't sure about is the size-- I already love the ergodox I've been using for the last 6 years, and reddit says the moonlander is much smaller feeling.
Huh, smaller could be better. I have huge hands but do not utlize a lot of keys on the Ez: I basically use home row and the big buttons in the thumb cluster ...
If you have smaller hands, consider a Kyria. I use an Ergodox EZ and while I'm generally happy with it, it's quite difficult for my thumbs to reach all but the first key in the thumb cluster.
Now I've only used one split keyboard and only for about three years. The Ergodox Ez. And I think it combats every aspect you've pointed out, except the part about it being expensive.
However, put that into perspective and it feels like this keyboard will outlive me. I'll probably get another one for home use when I can go back to the office...
I like that it allows me to open my chest a bit. I keep the two halves pretty far apart. It's genuinely made a difference in terms of shoulder and back pain.