I usually use Italian Flavored Breadcrumbs... or for chauliflower, for a sweeter taste, corn flake crumbs...
Panko are OK, but they don't toast as well, and if you use too much butter, they tend to get soggy, as they absorb a lot more of the butter...
I love Panko, but not for toasting in butter...
a heartier, denser bread crumb works much better... IMO...
They get nice and crunchy...