I have mostly SSD drives, with one "other" kind of drive. So I had to install there as it recommends not to put the working file on an SSD. No biggie. But when I save a flight, it goes to that other drive. I can point it at my P3D document folder, and it "looks" like it is there, but the flight planner won't find it and load it. If I put it on the working drive, the same pln file shows up then works fine.
The info on the map is MUCH BETTER than Plan-G. You can quickly grab ILS frequencies, etc by checking the "info under mouse curser" option. Also you can use a ruler (turn on an off) which gives you direction and distance to any point on the map without having to open another window (Plan G "info" panel). You can put many "kinds" of maps up, changing on the fly. If you see a road and want to know what it is, you put up the MapQuest map, if you are looking at a lake, you can use the satellite hybrid. Bottom line, many options on the maps.
I get a 404 on the forum, maybe it just isn't "up" today.