I bought a pair very similar to these
http://www.ebay.co.uk/itm/Mens-Moto..._Motorcycle_Trousers&var=&hash=item5f85b0fb5a
in June last year, and tend to wear them most weekends as normal jeans (they are heavier than modern jeans, like they used to be way back when stuff was made proper) I wear them when I'm just buzzing around town usually, but have worn them on longer journeys and have not "felt unsafe"
The ones I bought were about £40 plus £5 P&P and were listed as waterproof, which they were for a week or so until it "wore off" I have used various types of waterproofer on them since but it never seems to last more than a week or so, so it's cheaper to have a pair of over trousers for the wet stuff.
Anyhoo, they are good and tough, although I have not had to rely on the Kevlar lining or the free CE knee and hip Armour that was included.
I am now looking at buying another pair of blue ones, and I can't really see why you need to spend upwards of £150 for a pair of jeans with a label on, and yes , I get the "you get what you pay for" thing, but surely Kevlar is Kevlar is it not??
I would be interested to hear from anyone who has had the misfortune to have test the strength of this product in an accident.