1) echo is more middleware compatible - it's a PITA to use a lot of "standard" Go middleware (e.g. nosurf) with Gin, but echo has no problems with these.

2) the function signature for handlers always returns an error - so you have func(Context) error rather than func(Context). This feels a bit more like idiomatic Go, and makes it easier to write generic error middleware for your app.

In terms of performance, for all intents and purposes they're about the same in real-world cases (the Go community for some odd reason loves bikeshedding over router benchmarks, but in the real world this is probably the least of your concerns).