I have had an Unger pole (up to 42ft) for the last 3 years, and it's been the only pole I've had (apart from a couple of very short ones for shops...and they're Unger too
) Pole hose is on the outside...never had a problem with it.
It doesn't look as neat as through the pole, but it gives you far, far greater versatility!
It means that you need only use the length of pole you have to use, which also means you don't need several brushes for your several different length poles.
Being able to break the pole down and leave behind the sections you don't need makes life very much easier and lowers strain on your body.
My aluminium pole is now my back up pole as I've gone the modular route with the Gardiners Supalite pole, and that too of course has the pole hose on the outside.
There are various ways of keeping the hose tight to the pole in use, you can twirl the pole, wrapping the hose around it, you can use double sided velcro.
There was a Canadian guy at the NEC who had developed a smart clip system (a bit like the clips you see on central heating systems, the pole hose is just pushed into the clip and held in place...
damn good idea I thought.
Others have used curtain rings I believe.
Ian