They are far better than all the generic cheap off-brand tools you get from Argos/B&Q/Amazon etc. I'd say the quality is far closer to the big brands than it is the cheap stuff. It looks to me like they basically copy the Bosch product range.
Last year I think CH4 did a programme on ALDI/LIDL products and they came out very favourably against the bigger brands.
ALDI have now released a Ferrex Pro range which I tempted to get.
Back in the 80s I went to a specialist shop to buy a name brand hammer drill and took over £400 with me.
I knew the bloke in the shop and he pointed at a KRESS hammer drill and said "Buy that".
I said I wanted a name product that would last and he said that Kress made Makita amongst others but they sell the same products for half price with their own name on.
It's still going strong.