Just received my MiniMag Pro+. My first week's impression is: It's a winner if you liked the form factor of the MiniMag. As has been mentioned, it uses a traditional twist down tight to shut off, slightly loosen to turn on and continue rotate to focus. Unlike the old incandescent MiniMag, the new Pro+ has very little focusing range, but there is some.
The Pro+ does indeed have 2 levels. If the head is pointed down, when you turn it on, it comes on in the low level. This feature is one-handable too.
Here are some comparison shots:
The Pro+ is slightly longer, due to the head shape:


Very similar head diameter, however:

Test beams:
Pro+ High:

Pro+ Low:

MiniMag Nite-Ize:

In reality, the Pro+ Low is very similar to MiniMag Nite-Ize in light levels.
The body and head is of the same high level finish as the traditional Maglite models.
I don't know if the Nite-Ize tail clickie will work on this unit, but I don't see why it wouldn't.
IMO, this is a clear winner for Maglite.