I used a backpack on a trolley for 18mths then changed to vanmount 8 weeks ago.I've got through most of my round since changing.
It is so much easier and quicker,no more lugging 25 litre containers about or refilling them every night.I used algarde silicon hose with the backpack and it used to catch on everything and drive me insane,but with the microbore it hardly catches on anything.
I did buy an slx pole at the sametime which made life easier,only having to use one pole for everything.
I use a 300 litre tank but usually come home at lunch time, so I top up then if needed.It gives me the use of about 500 litres in a day,(still only got 200 litre water butt in garage) but rarely use more than 300 litres.
I wished I'd got a better hose reel,it only just holds 100 metres but keeps comimg of and jamming it up,have to get this sorted.
For me the vanmount is far better, it might depend on your type of work,I do mainly largish detached houses,anyway good luck with it I'm sure its a good move.
Billy