I have one in my big viv and they use it alot for getting up to the hammock and i've also seen Ginge rubbing against it to start off his shed so yeah i guess they do appriciate it. Sorry no pics at the mo but i'll endevour to get some.
James has some vines in his viv - we didn't think he ever used them, but one day he was laying on the lip of his faunarium lip (and it's one of the high sided ones) so he must have climbed up them!
Like Tizzy says, they're quite rough as well so good for shedding. Only downside I can see with them is that they're quite hard to get poo off (due to their rough texture)...
We've just swapped our snake to a larger but lower viv so the vines are now in an S shape across his tank.
The blue box is his wet sphagnum moss hide so that isn't in there all the time - he had a dreadful shed last time so this time I wanted it to go well, and last night I saw him hanging out of it and his colours were beautiful! Found a complete shed in his fake plant last night so very happy!
The little blue procelein table my daughter bought from a pound shop so we can put his mice on there at feed time! Looks a bit too much like a sacrificial offering to me but James doesn't seem to mind!