There's been a few threads on here about this, have a search.
I have had Draggin Jeans and now Hood. IMO i'd go for hood, mainly because the kevlar lining goes nearly the whole length of the leg. Draggin jeans have 'patches' of kevlar and as the leg length comes in one length and you have to shorten them I found having short legs (29") which meant the protection didnt cover the parts of my legs I wanted them to, above the knee. Hood jeans will also accept armour fixed with velcro and available at a bit more money. I wear the jeans all the time, 15 mile commute to work and legs did get a bit cold when temp dropped to -3c.
There's videos on youtube showing a guy being towed along the ground on his Draggin jeans and no damage sustained.
I was knocked off my bike 18 months ago, I had a broken leg and ligament damage but no gravel rash, probably due to the fact i went skidding down a grass verge and not the road.
A while ago a fellow Tossers lad (may have been Crapauld but not sure) came off his Scoot, the paramedics were impressed with the lack of injury due to his Kevlar jeans