Note, that a lot of digital audio gear comes with latencies of 5ms or
more. IIRC the Behringer V-AMPs have latencies of > 5ms. I own one of
the smaller V-AMP multi effects, but prefer my analog Boss, VOX,
Ibanez, not regarding the latency, but because the analog effects are
much easier to use. Anyway, don't expect that latencies between 1 ms and
5 ms are wide spread values.

I dunno man, are we talking about professional audio or are we talking about a cheap guitar processor? What standard are we holding a Linux solution to when we say it is for 'professional' use?

Latencies between 1ms and 5ms are ABSOLUTELY wide spread values in pro audio. Just off the top of my head an LS9, or an M7CL, or even an X32 are closer to the bottom end of that range. So is a PTHD rig. The dbx speaker processor I'm using is 1.8ms.