xwing is easier to fly and maneuver. the tie fighter (to me) is a bit slower. so locking on to tie fighters is easy for me, but on x-wings it takes me more effort to predict the flight escape they make when i lock on.
also dont forget that AI has a predefined route of escape from your lock, and generally you will memorize their pattern and be able to destroy them. whereas, real life players each have their own mentality. i've had a guy pull brakes when i was locking him, and he ended up behind me and took me down. its not as easy as hitting AI.