Multi OS is new to me. I got a new PC and migrated to SSD. I like the idea of having multiple OS environments (work, play, experimenting). Switching between drives via BIOS and physically switching SATA connections seems straightforward. Also moving about partition images.
Multiboot would add a degree of versatility and make better use of drives. Then there's virtualization possibly. Both seem to be more intricate.
(Thank you for the EasyBCD suggestion)