A better question would be, are you even in the market for a switch to a different VTT? And my answer is: Heck no!
I'm already using Foundry VTT, and I would not see a reason to move to something else. While I do self-host FVTT (on a dedicated Raspberry Pi 24/7), it was more the option to self-host that attracted me to FVTT, just like the option to expand the VTT yourself (or via third party). So unless FVTT suddenly stops completely (no more updates), I can still run it for at least a decade after it stops being updated.
I'm also wondering what kind of position someone takes up in the market, we already have Foundry VTT, Fantasy Grounds, Tabletop Simulator and TaleSpire as self-hosted options that all fulfill a different niche. FVTT also popped out due to it working in the browser (limited selection supported)... What niche would your VTT fill in the self-hosted space?