GME Parabolic Springs

Has anybody got any experience of GME parabolic springs?

Island 4X4 are selling a full set on Ebay with all bushes, shackle bolts and U bolts, including VAT and delivery for 206 quid.

So they're not much more than Paddock's, and the rear ones are propper 3 leaf springs as opposed to 2 leaf plus helper.

Seems cheap, but are they any good?

http://www.gmesprings.co.uk/

I Brought a set a about 6 months ago from Island 4x4 they seam fine ride is much better and even when loaded the rear spring do not seam to sag unlike the standard ones which used to hit the bump stops and break your teath. I have also used it in a few trails and have not mangaged to break them yet. So Can't be to bad.