Personally I prefer an Aluminium greenhouse for the simple reason that they don't need much looking after !
Wood can warp and needs treating every so often and it's one hell of a job in my experience !
I've currently got an 8ft x 6ft Gardman greenhouse but I'm very tempted to go for a bigger model now. I like the look of the Elite Classique 12ft x 20ft in Green from
www.ukgreenhousesales.co.uk. At under £1500 it seems decent enough:
Elite CLASSIQUE 12ft 6" x 20ft 5" Greenhouse - Greenhouses UK - All Leading Brand Greenhouses
Thing is I'm not sure which glazing to go for this time.