About what I'd expect for the first benchmark, but that's the kind of intervention from the user that I think frameworks should not require. The time still spent by Backbone.js on the second one more or less illustrates why I don't believe in event oriented MVCs.
I'm getting pretty good results with swannodette's benchmarks - http://danshearmur.github.io/backbone-fast-view/
I'm getting approx 150ms in Chrome for benchmark 1 and about 400 ms for Chrome for benchmark 2