Is there much of a difference between Quick Detach Mounts (QD) and Regular Mounts?

● To mount/unmount a QD I don't need an allen wrench.
For a regular mount, I do need Allen's help.
● And if the QD is a nice lever, it's a very quick operation — whereas Allen takes his time rotating several times around his axis until he screws up (or bolts up) the picatinny brackets.....


▪ A difference in tightness and stability?
▪ A difference in height? (I noticed that QD are usually not among the lowest mounts available.)
Thanks for your input.
Matthias