The eDrive takes up very little space, and it is easy to boot into.
As far as the upgrade price is concerned, I don't mind spending $29.95 for the upgrade, as well-developed and supported products are like gold! I did the same for SuperDuper! (only needed to do it 1 time), and still do license renewals for 1Password and ClamXAv. If I were using Carbon Copy Cloner, I would not balk at paying for the upgrades they require to stay current.
Again, excellent software deserves our support. And as I have stated, by performing my own cleaning efforts, and using Onyx and Tech Tool Pro (a proven and winning combination, at least for me), my machines run error free, ie, "lean, mean, and clean".
Finally, your correction about Tech Tool Pro 13 being compatible with Big Sur is still mistaken. It is not compatible yet, as I pointed out with that link above. I suspect the next version, V13.0.2, or V13.1 (whatever they call it), will be compatible.
