I've just converted to Microbore, the only problem I have is a leaky non return valve thingy that you push the pole hose into
With 100m of microbore you need a 100psi pump, my 60psi wasn't up to it...which I kinda guessed it wouldn't be.
The brush (Gardiners Superlite) came fitted with two 2mm needle jets, and even at 35 feet the flow is plenty for my needs, prior to this I was using needle jets in a Salmon brush (Peter Fogwill) but I found that with the needle jets you need a greater pressure/flowrate to get a decent 'fan'.
With the needle jets I've found I can cope with a lower flow rate without compromising on speed or quality.
Though the microbore I have is that supplied by Gardiners, I don't know if all microbore has the same internal diameter, and that makes a big difference...
Ian