I've used Parallels since the first version but recently switched to VMWare Fusion.
When it works, Parallels works just fine. However, I have had several experiences of 'losing' my VM images - twice after OS upgrades, and once during a disaster recovery full disk restore from Time Machine backup. Parallels worked fine, but my VM images just 'could not be found' by Parallels, meaning I had to recreate the VMs from scratch. Now, this may have been through some odd stupidity on my part, but I have 35+ years of IT experience and a fair understanding of the apps, restore and upgrade processes, etc. so my experience in this regard was not 'normal' or expected.
i have no idea if Fusion will be more robust for me going forward, but I decided I was tired of 'surprises' from Parallels.