Nikwax Analogy (Paramo) fabrics and Gore-Tex fabrics are very different, and in fact fall under two different categories: Nikwax is more of a softshell and Gore-Tex is a hardshell. That means Paramo is not 100% waterproof, even when treated while Gore-Tex fabric is (when well maintained).
The fact that Nikwax fabric is not completely waterproof means that it is much more breathable and comfortable to wear when active, but facing a down pour water will get through. Gore-Tex on the other hand is a waterproof/breathable fabric, but offers much less breathability compared to softshells.
At the end of the day the question is what you are trying to get: a waterproof shell or a comfortable and breathable softshell? That will depend on the conditions you are usually at, NW USA or Scotland, I'd go for a waterproof shell as the chances are very high for rain and temperatures are lower. If you are in warmer and drier (rare rain storms), a softhshell with a really simple (and cheap) emergency shell for those few minutes of rain.
It is important to remember that there are great alternatives to both fabrics: eVant is also a great breathable hardshell while most companies have a synthetic softshell that will work just as much.
Pick what you are going for and buy accordingly.