Spud --
I wouldn't go for any laser tracker that doesn't have an absolute distance meter. Earlier-generation trackers used a laser interferometer distance meter, which requires continuous measurement of Spherically-Mounted Retroreflector (SMR) location. No beam breaking allowed, although newer versions of the interferoneter tracker automatically pointed to the most recent recorded location rather than having to go back to the SMR nest on the tracker base.
I haven't seen any tracker software that is a better fit with my own thought processes than SMX's Insight, but Insight went away with Faro's purchase of SMX, which is now decades past.
All in all, I'd lean toward Spatial Analyzer rather than Faro's -- I've forgotten what it's called -- successor to CAM Ii.
You did ask about Laser Trackers, but you mention Nikon. To my knowledge, Nikon "Laser Radar" is not a laser tracker, but Laser Scanner with the accuracy of a Laser Tracker. I regard the Laser Radar to be the bell of the ball, but the last I heard, the starting price for a new system is right at $US 750,000 . . . nearly 20 times that is an entry-level Laser Scanner, and 10 times the price of an entry-level Laser Tracker.