Excellent review, as always. I've just gotten a 3rd NMB keyboard (two RT8255C and an RT101), all three with the "clicky" space invaders.
I'm glad you highlighted some of the quirks of the keyboard. One thing that is especially notable is the gap between actuation and the click, as when you try to type very softly, you can avoid the clicks. This can actually be kind of difficult to avoid errors though since if you type this softly, you'll likely end up with some keys clicking and some not.
Another interesting thing is that you get one click for the downstroke and one for the upstroke. However, there is a point between them at which you will only get the downwards click (if you stop just after it) -- the same goes for the upwards stroke if you stop halfway, but this isn't useful.
You can also remove the clicker piece (the white plastic bit) and end up with effectively linear switches. I made the spacebar and most modifiers linear and it's quite pleasant this way. I also swapped the heavy spacebar spring with the Pause/Break key so that the spacebar isn't so heavy.
The one I just got is brand new. I'm hoping to try lubricating one of them to see how it is.