I am with you on the fence, having a wide range of handhelds, including GBC and GBL. Just can't take my eyes of this little charming device, but always postponing it in favor of some other stuff. So my thoughts...

I am interested in romhacks of Pokemon. PSP and PS Vita are my choice for GBA romhacks (I prefer them over AGS-101), but I want something with GB form-factor for GB and GBC titles. In this way "Odroid-Go" looks like GBC + backlight screen with adjustable levels and palette + reasonable battery life + savestates + an option to setup RTC on each emualator run (if I understand meaning of this build https://github.com/pelle7/go-play/releases/tag/pelle7-20190707-testversion correctly) or with rom hacks. The latter is a big deal, considering "Everdrive GB X7" price.

When and if I will manage to apply some integer scaled backlit GBC mod and will buy a real RTC cartridge, like X7 or modern ElCheapo, Odroid-Go will have only a battery advantage in my eyes. But before this, I see no other copetitior in GB form-factor for this price.