Some, like Toothsome, seem to be harder to walk up to, so definitely consider reserving a few days ahead. We had luck at Antijitos, Big Fire and NBC Sports Grill with this, and it's useful all restaurants seem to use the same reservation system which texts you when your table is ready.
There's several very large restaurants and most you're able to go onto a waitlist (normally around an hour) during quieter times of year (no booking 60 days in advance). I was sick of barbershop quartet versions of Christmas songs at Disney Springs, but Universal's playlist was awesome. I think having been to Disney Springs, there's a few quick wins that could elevate Citywalk higher, but generally it's a really nice place to hang out. It also looks great with the lighting, the lake/river running through the middle and the various photo opportunities this affords. I really like the layout of the whole Universal Orlando resort, especially how Citywalk fits in between the two parks. Really love the vibe of Citywalk, especially at night.
