Flight wise-cant beat the 109 for ease of flying.
P-51 has a very big learning curve, the spit is a bit more forgiving.
When most of the fighters in game stall its violent, throws the aircraft around and can put you on your back. With the 109, the nose drops. That's about it.
Also you might consider the Zero.
In fact, you should look into Joint Ops. Id recommend it for any new IL2 pilots.
http://www.joint-ops.com/php2/index.php
If you have the time they have great teachers that will guide you through most of what you need to know.