I had a £800 jobbie fitted a year or so ago. My first non-up and over so have nothing to compre it to, but it's been brilliant. Looks excellent and as good as when fitted, works a treat, has had a few things bashed into it and it's fine, the garage is noticeably better insulated. I don't really k ow what a more expensive one could do better.
Though mine is just satin black...I suppose I could see paying more for wood effect or something.