Just about a perfect description, except mechanical lockers don't always do a 50-50 split, sometimes they slip.

The mechanical sounds like the best, but air and electric air (IMHO).

When they are disengaged, there is nothing going on. No parts wearing, no noise, nothing to break.
With a mechanical locker, the parts are always wearing and making noise. They also offer up some od handling characteristics while cornering (depending on design).

A lot of it comes down to personal preference though.