Half car covers

Has anyone used a Half car cover? I am looking to protect my mohair roof over winter as it stored outside, so wondering if anyone has any experience of these?
http://www.carcovershop.co.uk/Waterproof-Car-Half-TopCovers.asp

Had one for our MGF a few years ago. fitted well, we used it all year round as roof was a bit leaky.  Water did eventually soak through but was well worth the protection it offered.

Ours deteriorated after a couple of years, but bear in mind all year round so sun damage in summer plays our cat used to sharpen its claws on it.

Only real issue I think is that the elastic straps which go to wheel arches can rub on paint and you can get some light marring of paint - fixed with some T cut though.

I had one on the cab

Worked well over all the only issue is it acts like a huge sail when it's windy but mine was just a cheapo one off eBay

those half covers are a bit expensive, i got a tarpaulin sheet from go outdoors camping shop fo 20 quid

I never cover mine.
Covers tend to rub the paint.
Blow about in the wind and can trap moisture which can blister the paint.

Washing and putting a waterproofing treatment on the roof is the ideal thing.
Ragg topp or 303 Aerospace ideal choice.
I also have a Kampa damp buster inside the car too.
Fill the top with crystals it draws the moisture out the air. Just have a look and empty the water once a week. I start mine run to temperature and drive back and forth up the drive just to keep the wheels free.
What's really important is making sure you clean your scuttle drain holes out and the holes on the bottom of the doors too.
Make sure your vapour barriers behind the doors are good. You can add a flap on the back and divert this into the door so if your scraper seals are perished and digest of water that goes past them just flushes out the bottoms.