Recently replaced my old cylinder vacuum with a Shark Pets lift-away upright one after pretty much everyone seemed to say uprights are the way to go. I'd never used one before.
I hate it.
It's really, really heavy. The lift-away design means the dust canister part (that's meant to lift away) keeps falling off the wand part and most of the time it's easier to just carry it around separately since it keeps falling off anyway... It's almost impossible to vacuum area rugs because the brush head thing just gets stuck to them if moved back rather than forward. Storing it is a pain because unlike the old cylinder model that stored the cord inside, this one just has a "hook" on the side to hang the cord from but it's not particularly useful at all. I probably should have chosen a cordless one so the last one's my mistake.
So why does everyone rave about uprights? My old cylinder vacuum was light, easy to move around, small to store... The only good things so far have been the ease of vacuuming stairs, and the amazing suction power.