There is a big difference between then but it’s not what you’re saying.
Both Returnil and TimeFreeze can have only ONE snapshot (and it is NOT a complete clone of the OS or backup).
Comodo Time Machine could allow 1000 snapshots of the full system…
Of course there is a lot of differences.
Comodo Time Machine takes snapshots of the disk “surface” (technically, the sectors of the disk) and you can restore all your system (with all files, folders, settings, registry, etc. etc.) and not only some files and drivers like the problematic Windows System Restore one.