To be clear, IMHO, Deno looks fine for what it is. The features are great. The cons ironically mostly boil down to "it's not node", i.e. ejecting a non-trivial app from CRA into some vite setup is doable with some effort, but migrating to Deno is, charitably, likely a monumental task that nobody would ever undertake, even considering the upsides.
At the risk of diving too deep into opinion territory, I'm not all that enthusiastic about isomorphic JS (and I say this as a someone who's worked on a isomorphic framework). The promise of low learning curve is certainly appealing, especially for those still in the learning phase, but at least in my experience I find that isomorphism falls a bit short in practice because server and client semantics are just... different.
When I talk about compatibility, I'm specifically talking about non-platform compatibility, i.e. library authors need to consciously target Deno if they want to support it, and the way to do so may be entirely non-trivial (e.g. the lengths that postgres.js goes to, compared to slonik, comes to mind). But most of the JS ecosystem lives on NPM and imports things willy-nilly with no regard for whether their thing will work in Deno because that's the path of least resistance. This is not Deno's fault of course, just an unfortunate reality.
At the risk of diving too deep into opinion territory, I'm not all that enthusiastic about isomorphic JS (and I say this as a someone who's worked on a isomorphic framework). The promise of low learning curve is certainly appealing, especially for those still in the learning phase, but at least in my experience I find that isomorphism falls a bit short in practice because server and client semantics are just... different.
When I talk about compatibility, I'm specifically talking about non-platform compatibility, i.e. library authors need to consciously target Deno if they want to support it, and the way to do so may be entirely non-trivial (e.g. the lengths that postgres.js goes to, compared to slonik, comes to mind). But most of the JS ecosystem lives on NPM and imports things willy-nilly with no regard for whether their thing will work in Deno because that's the path of least resistance. This is not Deno's fault of course, just an unfortunate reality.