I downloaded the free trial of PhotoLab and gave it a whirl. The most important thing I found is this is NOT the mashup of NIK Tools and Optics Pro I, and I think many others, were hoping/thinking it would be. PhotoLab, from what I can tell, is really Optics Pro with U-Point Technology laid over it. In retrospect that makes perfect sense; U-Point is the Awesome Sauce behind Control Points and Control Points are the "crown jewels" of NIK. Control Points are what elevated NIK from just another set of filters you slap on, a la Instagram, et al. to a truly powerful and useful editing tool. I was thinking Photolab was going to be NIK's resuscitation, but ixO seems to have simply incorporated NIK's U-Point Technology and, sadly, nothing else.
The implementation of CP's is a little different in Photolab, as is masking them, but if you already know how to use positive and negative CP's and how to mask them in NIK, you should have no trouble figuring how to do the same things using PhotoLab. The GUI specifically attached to CP's is better in PhotoLab, I think, with a bigger set of adjustments to choose from, including things like sharpening. The sliders are arranged vertically, like the sliders on a stereo equalizer.
PhotoLab, to put it succinctly, appears to me to be Optics Pro with Viveza layered on top.
So, if you are a die-hard lover of NIK Tools, and by that I mean if you turn to it for Silver Efex Pro, Analog Efex, Color Efex, etc., you are NOT going to find those filters in Photolab and you'll probably be disappointed. If you're a die-hard Optics Pro user, you'll probably find the addition of CP's a nice addition to what Optics Pro already does.