Just to address the fps/lag issue since I've had some time to mess around with the game for a bit now. Firstly, the Switch version is NOT locked to 30 fps, I got confused since the menus were clearly smooth but my capture card kept showing me a 30fps feed so I thought my eyes probably degraded a bit and moved on. After streaming/playing some more I realized my capture card can't handle 1080p60 and drops that to 30fps, which led to the confusion.
However, there is a LOT of framerate issues on the Switch release, that seem to be absent from the PS4 one. It's really about the same as you'd get on a lower end PC, some slowdown on specific spells, lots of it on others, and some noticeable drop in framerate as you fill the map more and more. If you idle after entering the dungeon for the first time, the game stays at 60fps stable, but then after I mapped out all of 1F it seemed to drop to 45-50. It's noticeable when comparing them, but really doesnt get in the way at all when playing. Obviously stuff like Nitori's Extending Arm tanking the fps to 15 as the spell "explodes" is a lot more intrusive.
Again, all of this seems absent on the PS4, making me believe they either prioritized that or didn't test Switch enough in docked mode. Or you know, maybe the PS4 just has a lot more power than the Switch.
I'll play some more on portable mode tomorrow to see if it gets any better, but I doubt it.
As far as the Switch version goes, I feel like the game would run much, much better if they targeted 720p60 instead of 1080p60, given the history of poor optimizations going on in the original PC release. And then in portable mode drop some of the particle effects to reduce lag, or maybe even lower the target resolution a bit. Heck, I'd be fine with a stable 30fps, it's not like there's much going on anyway, and it'd be a decent compromise when playing on the go. Which to me is the biggest perk on the Switch release, anyway.
To sum it all up, I'd get the PS4 version if you have the option and don't plan on playing on the go, but tbh waiting for the PC version might be the cheapest and best option in the long run, what with the lower price and possibility of English / misc. patches.
Also I like the new Rumia, she looks cute!