A resonance realm is described as feeling similar to a UV node for a technomancer. The following is a bit of fluff describing a resonance realm, but I feel like it could also be applied to a UV node:
There is a certain feeling that every
technomancer knows when diving through
the Matrix. It's more than the
constant buzz of data traffic in the
background, it's the feeling that
there is something larger beyond the
curtain of icons and background
processes. Or perhaps it's a feeling
that there are massive depths lying
beneath the surface of the Matrix,
unexplored and unseen places from
which Resonance seeps into the virtual
realm.... On the other side, they
discovered unique places, thriving
with sprites, lit from within by
abundant Resonance that shone as
bright as the sun.
(Unwired p. 172)
This is an oblique answer, I don't know if there's any more detailed fluff out there. The following is my own interpretation/imaginative filling in the blanks:
My feeling is that each UV node is different, and the feeling you get from it would depend on the sculpting and theme. A UV node feels hyper-real, so it might be a symphony of soft breezes that touch every blade of grass, or a shot of adrenaline like waking up in mid-fall. I think I would give the technomancer a stronger-than-usual impression of the theme; it might be overwhelming. UV nodes cause reality filters to fail, and override the user's iconography with the system. Maybe the technomancer would have a hard time distinguishing between the node sculpting and the real world.
Think of the Matrix, from the movie, as a UV node. To a technomancer, maybe it seems real, but something's just a little "off", "like a splinter in your mind", etc.