I've had one for a year and 10,000-odd miles and I really rate its versatility. For a touring holiday, for example, I reckon it's hard to beat.
As mentioned above, you can't have a cool, waterproof suit as the waterproofing is in the lining, but it is so cool when the weather is warm that I can live with that. When its seriously wet, it tends to be cooler (in Europe, anyway). I've never had a problem with billowing - just make sure you open the rear zip.
I bought the trousers as well which, in addition to looking nice and smart so your mum can be proud of you, gives another fully waterproof pocket.
I reckon it looks better when it gets a bit grubby ...
Mine is 100% waterproof with the lining in. however, it isn't as warm as a "proper" winter Jacket and trousers - I use a Richa lined jacket and trousers for really cold days.
Finally, what is all this stuff about £10 suits at Kelso?
Robin.