Crazy good performance from the 2017 4k iMac now the Fusion drive has been replaced with an SSD. there’s been a reduction in overall capacity, the Fusion drive was a 1 TB HDD attached to a 32 GB SSD. Big deal, I was only using 190 GB anyway.
Apps are much more responsive, opening faster, bootup is 55 seconds rather than 5 minutes. money well spent, I think. I’d initially thought about upgrading to a 5oo GB SSD but the quote from the Apple reseller’s service dep showed a 1TB was only $60 more than a 500 GB. Easy choice.