Signed up a couple of years ago and for a while it was quite good. Seemed to build up points quite quickly, there was always extra points on offer, like spend £5 on laundry and get 50p or whatever. That's all gone, my current offers are only for non-grocery products like garden furniture and barbecues, and I have had 86p in my cashpot since December.
Asda seems to have really lost its way, it's the biggest supermarket round these parts and was significantly cheaper than Tesco/Sainsburys for a long time. But that's not the case any more, they just seem to be struggling and although I am well prepared to be told i'm unreasonable and people are regularly getting £5 off their shop, it just doesn't seem like that.
Disclaimer: I know the supermarkets owe us nothing, and that everything's a bonus etc etc. But I'd rather just go to Aldi which makes no pretence about rewarding loyalty.