Best I’ve worked on were Hormann by some distance. Excellent build quality with fundamentally good design.
Had no experience of Crocodile but they are just a basic plastic roller shutter door, however with all the advertising they’re doing it’s unlikely they will be cheap. Those adverts have to be paid for somehow! I suspect with national coverage they may sub contract the work out so worth checking!
If the Crocodile style appeals then check out companies like Thermaglide and Novoferm. I’m pretty sure they’ll be better value.
My advice, also go to the Hormann and Garador websites and contact your nearest dealer / installer.
Ultimately you need to decide which style you prefer. The Canopy up and over style overhangs the entrance which is hand if your emptying you car boot in the rain but requires adaptation if you wish to motorise.
Retractable doors generally have a less complex mechanism and have the advantage a motor can be added easily. Future servicing or repairs are easiest on this type of door and easily done by the owner.
Both the above have plastic strips at the sides of the panel but are not strictly watertight!
Roller doors in metal are generally noisy and best kept for commercial premises however some of the plastic ones are ok but I certainly wouldn’t have anything of great value behind them as the are pretty flimsy!
To me Sectional doors have always been the best quality offering an almost airtight seal to prevent the elements getting in and are available with insulated panels as well if you work in the garage or it’s attached to your house.Easily maintained and an electric operator can be added cheaply as well!
Just noticed you’re in Glasgow so worth checking these guys out
http://www.thedoordepot.co.uk/
Not sure how far west they go but I knew someone who works for them and they are good people.