As work involve with putting the edging in and if it getting brittle or rotten after a short while - it is a pain to see it- so I always make sure it will be proper edging. there are 2 great edgings for much less money at

www.best4garden.co.uk

the heavy duty is very similar to the smart edge but without the clips on the top. The fact it is deeper keep it in place well, but also stop roots from going under.
Also they are both made from recycled plastic!