I do a combination shop, some asda and some Aldi. They're very close on most prices. I like Aldi meatballs though.
The thing with Aldi is that for some unknown reason I always end up with a few random items that I didn't plan for. And yes, the whole race to get you out of the till area really makes me uncomfortable and slightly stressed!
Asda definitely. Aldi make me feel despised. The disproportionate ratio of security staff to checkout staff, the suicidal looks on the checkout staff's faces, that feckin race to scan your stuff and then tell you to pack it 'over there' - makes me feel like a leper or in some sort of ghetto. I also don't find their basics cheaper than Asda's own brand at all. I only go to Aldi for the interesting European chilled foods these days.
Shopped recently in Asda as they had some good offers on wine and beer. I took the opportunity to do a weekly shop. I really wish I hadn't. I though the quality was rubbish. I then remembered that a year or two ago when I had done the same thing I told family to remind me never to do it again. I forgot this time. Won't be shopping in Asda for a very long time.