<font face="Verdana, Arial, Helvetica, sans-serif" size="2"> key is research to determine if the benefits will fit your travel patterns</font>
That is priority pass in a nutshell. I too have times when it works out great and others when it's a washout. For me, it mostly works out and it's benefit (which is included with my UK Amex Card) outweighs paying for RCC for the few times when it doesn't work.
Most of the airlines do exclude the major hubs as that is where you would really want to use it. But I can live with that rather than paying $350 for a few lounge visits. Most of my UA hub visits are travelling internationally, so *G/upgrades take care of that for me.