I think tow-boot is mostly useful for ARM64 (where there's the potential for UEFI goodies)
Beyond that, it sounds like a modern, bloated version of u-boot+bootmenu that N900 already has.
Additionally, at least I don't see how it would work on N900, since even vanilla u-boot 'fits tightly' on it afaik.
The other main Leste target device, the Droid 4, doesn't use u-boot to begin with.

Anyway, just my own opinion for now. Maybe I'm just stuck in the past :-)