My experience with corrugated PVC has been very very disappointing - it can lose its elasticity after 2 years in UV and when that happens the only thing that will stop it shattering is the rigidity of the framework holding it. This kind of 'battleship' engineering costs more money than it is worth, and a similarly rigid triangle-braced structure is more trouble than it's worth.
If you are re-roofing a structure that was designed to carry the weight of a tile or slate roof then maybe it will last 5 years, but otherwise forget it.
If you are building (or have built) a framework then it is more cost effective to use 10mm twinwall polycarbonate that will stay strong and durable for decades - even though it costs 2-2.5x as much up front - and the same goes for any frame you can buy at a reasonable price.
4mm horticultural PC is cheaper but much more flexible - big panels will need to be braced across to stop them popping out.
Cheers.