Hello Steve, welcome to HPC:Factor.
Couple of model number typo's there. There wasn't a 630, it was the 620 or the 660. Same with the 780 where I think you mean the 720 - the 780 was an NEC Model. See:
https://www.hpcfactor.com/hardware/devices/default.asp?page=showOem
I prefer the styling of the 720 too. I never liked the duck-egg silver of the 728. You can run the 720 ROM in a 728 though if you want perfection.
Honestly though, unless you want to play with Deuvian Linux, most people can suffice with the 720's 32MB.