I finished 2 of 3 update / upgrades. Laptop - I upgraded from LM 19.3 to LM 20 and the upgrade went very well with only a couple of bumps. One desktop, I perform a clean install of LM 20 and that went very well until I try to remove LM 19.3.
I have one more desktop to install LM 20 onto. I think I will go with the clean install again and this time do the install over LM 19.3.
I wish you well with the upgrades. I have just fired up the Dell running ubuntu 16.04 LTS - Guess what another large 128MB zipped update! 
Feels as though performance is getting incrementally slower.
Stay Safe
I’m pleased that Linux Mint got rid of Snap packages, they are too heavy and a lot of them don’t work. I’ve said it before Snap Packages reminds me of Ubuntu Store from many years ago, with every Ubuntu release Ubuntu or Canonical kept saying that Ubuntu Store had been fixed, it never worked and so everyone used Synaptic. I know that Martin Wimpress from Ubuntu Mate is doing some work on Snap Packages for Ubuntu, but even so they are still way to big and slow to open.