So the philosophy here is that attitude is attitude, period. It matches how you'd fly when you look out the window. The pitch adjust isn't meant to correct for parallax like an old attitude indicator, which is really meant to adjust for different height pilots, not to reference the zero pitch line in different flight regimes (though I realize that's how it often gets used).
But, the really nice thing about the EFIS is that you have the flight path marker. This tells you not which way the airplane is pointing (which is what the attitude indicator is for), but where it's heading in space, relative to the ground. So if you want to hold altitude, just plop the flight path marker on the zero pitch line. You can be mushing along in slow flight or cruising at (just shy of) VNE - Doesn't matter. If the FPM is on the zero pitch line, you're not climbing or descending. Basically, set the pitch just once ever, to reflect when the aircraft is level in actual pitch attitude.
One other neat trick you can use the FPM for is to nail an approach glideslope. The FPM's vertical alignment on the pitch scale shows you the path that the aircraft is cutting through space. In other words, if you want to descend on a 3 degree slope, just put the flight path marker at -3 degrees. If you know the approach angle of your ILS or GPS approach (which is on the plate), just center the needle, assume the published angle, and watch as you ride the needle centered all the way down!
