Redviking, I havent used the peri system but I have loads of information and stuff on it , i have messed about with it at SED show, its a very good system but again horses for courses , companies need to look closely at the type of work they are doing, tube and clip is so adaptable so all street work companies in my opinion should have tube an clip.
if you do lots of big lump scaffolds and temp roof jobs where there isnt much in the way of obstructions yeah go for system poss layher good system.
if you do big construction type work you need both tube an clip and system possibly peri system because it is strong and very wide you can use a pallet truck on the lifts ideal for bad access or tight space sites where loading bays etc are limited, a big strong hoist and a couple pallet trucks can service whole scaffold, plus rubbish chutes down to skips below means very little plant needed on job
if you in the industrial work , its really your choice as little transport needed on main roads so its a case of what works best in your enviroment .