I would argue that the only trade-off is that my keyboard has no case or screws for tenting, I just use the bare PCB. In a future version I will add screws for a case and tenting though, then I would argue no trade-off when compared, for example, to the Cantor. (The Piantor has better microcontroller in the RP and the Corne just has amazing community support).
The thumb keys were only deal breakers because of my hands and condition at that time, I still think the Cantor is a good keyboard, but it’s just not for me. (I also like the thumb keys closer together!)
Oh, and I didn’t find any other keyboards like the Kaly. I did look for a while, but didn’t find anything like it, so eventually just decided to make my own! (I was quite against doing a full design at the start, but warmed up to it by the end).