As for it being flimsy, I can't say I agree with that... I actually thought when I bought it for the huge sum of £5 that is was quite a sturdy cleaner, and was made well.
Although, my Philips looks to have been a "back up" cleaner that never got used much, so perhaps your sister's Delonghi was more used and it got worn out.
Oh, and on a random note, I received my pack of belts yesterday that I ordered from eBay, and now the Philips works even better than before (I was using it with an old belt off my Turbopower which wasn't gripping the brush roll 100%), and that 800 Watt motor is so quiet and smooth!
For a 18 year old machine she works fantastically.