The CFS-2 Flight Deck

The M5 Zero is not a popular aircraft in the virtual CFS-2 skies, & for what reason I can't imagine... it may be the best-balanced of the stock aircraft.

*Faster than the Wildcat and M2 Zero > Energy tactics will be effective.
*Quickest roll rate in either direction of any stock fighter at medium to low speeds (At high speed only the Lightining has a slight roll-speed edge) > Done correctly, the Scissors in this plane cannot be matched.
*Capable of smaller turning radii of all aircraft except the M2 Zero & George at all but the highest speeds > Making a reversal from hunted to hunter much easier....
*Stronger weaponry than M2 Zero, & with machine guns in the nose that eliminate convergence issues... long range shots can be effective with pratice.
*Diving qualities far improved over the M2, especially with spoilers engaged, but still no match for the heavier US planes. > Do not dive unless you know you can score a hit quickly.
*Better climb rate than M2 > The mother of energy... use it wisely.
*Better-armored than the M2 and even the Wildcat > Don't be too quick to bail-out you might just make your opponent sorry.

Drawbacks..:
-Slower than all aircraft but the M2 & Wildcat < Learn to compensate for lack of speed with an advantage in energy.
- Lacks the super low-speed stability of the M2 < Don't be too quick to attack if the M2 can bring its guns to bear.
-Cannot out-climb any aircraft but the M2 & Wildcat < This will make energy conservation difficult... Don't waste too much energy in maneuvers.
-Lacks the firepower & armor of the US planes & the George < Head-on runs are never a good idea; learn to avoid damage in the initial merge, never fly a line during head-ons.
-Becomes unstable at very high speed dives unless spoilers are used < Use spoilers!

Generally, the M5 can out-maneuver anything that it can't out-run, & out-run anything it can't out-maneuver. Pitted against the Hellcat, P-38, Corsair, or the George, the M5 has the advantage in angles-style combat. Pitted against the M2 & the Wildcat, the M5 is at an advantage in energy-style combat... Essentially, against any foe, the M5 has an advantage somewhere, which isn't true for every fighter in the game, finding & using that advantage is up to you.

If you plan wisely, you may find the M5 to be the Jack-of-all-trades... Of course, if you plan poorly, you'll find yourself out-matched, & willing to call the M5 a poor compromise of performance.

Reference:
MicroSoft CFS-2 Pilots Manual
Sybex CFS-2 Manual
Article for Airwarefare by RAF_SmokyDaBear