When I was preparing my GFT in bournemouth, I used to simulate NavEx's on my FS98 (with additionnal UK scenery ) I was creating realistic winds based on winds aloft conditions of the day.
Because VDF was not a feature on the microsoft software, I was doing a VOR/TACAN fix instead of it (around yeovil) . The lack of landmarks for diversion or VFR purpose is easily overcome if you use towns , river or road to assess your position.
when I was simulating the instrument bit of the test (you know ? when they remove the panels and you can't find the bloody disused airfield
) I used to report the LAT/LONG (you can dispaly your GPS pos ) on the VFR chart so I knew where I broke out.
Then, after the GFT, I began the IR, and the sim was again a great tool. At this stage, I was flying a Duchess. Since no BE76 were available on the web for FS98; I customized a Baron.
By increasing the drag factor, decreasing the engine Power, I finally found the appropriate settings to re-create the Duchess flight model (more or less ).
In my humble opinion, Flight sims can't do no harm to your flight training (PPL , CPL ....) But you have to be aware of their limitations . If you plan to use microsoft's sim, be ready to spend some time on the web, looking for additionnal tools to taylor the sim to your needs ( You can create exaclty the same instrument panel as the PA28 of your school ! )
I don't know if it made me a better pilot, but for sure it gave me some confindence ... for a far cheaper amount of money than the "not so light" twin of the school.
Enjoy your flights !