If it's the initial outlay you are wanting discussed there is no comparison, tube is much cheaper obviously and to be honest I reckon whichever suits you best will depend a lot on customer demand and even where you live. If it's price to erect then system is again obviously much cheaper but some of the more complicated jobs whilst can be done with system doesn't for me make financial sense it just becomes really expensive to carry all the individual components which can sit in the yard for most of the year gathering dust just to be brought out from time to time. I also think rightly or wrongly tube can be quicker in these situations but it's probably more to do with the fact we have always used tube as a problem solver and maybe not used system to it's fullest potential. Our system of choice is Genlok, good all rounder for the basic jobs good reliable performance over time without costing the earth.