Mrs TB has had Dysons for probably 25 years now. 4 of them. And we still have all 4, all working fine. The DC04 has been relegated to garage use, she has a small corded one upstairs and a bigger one downstairs, plus a cordless V8 as a daily quick use jobbie.
The cordless is convenient for quick cleaning, but the mains ones pick up more due to better suction, so they get run around every few weeks.
Being uprights, and having to comply with EU rules we took on, they are reliant on the brush bar being in good condition. This is an item that wears, obviously. So anyone comparing a 5 year old upright with any new upright will see a difference. On any upright, the brusher needs to be in good enough condition to lift the dust out of the carpet.
The other thing, despite the marketing BS, the filter does need regular washing (the main filter, not the HEPA).
Only real issues we've had is the hoses splitting. Pattern ones seem particularly bad, but Dyson's could babe better, given the cost. The DC04 had a mains flex fail, and its switch fail.