You could always go the center ground and get the P14 or M1917. Then you have a Mauser/Enfield combination that takes the best features of all.
You have the strength of the 98 Mauser design, the exchangeable bolt head for quick easy repairs, the superior peep sight and a nigh indestructible rifle.
The 1903 and 03a3 are great rifles for target shooting, but they really should have rethought the front sight, for a battle rifle. It wouldn't have been hard to give it protective ears or a ring to prevent it from being knocked out of place, as it is kind of delicate. I do like the rear sight of the 03a3, even if it is once again more designed for thoughtful shooting, rather than the heat of combat, where you not really going to have much time to adjust the windage setting. It was a fine rifle, but with a few alterations it would have been perfect/the M1917. Unfortunately that rifle suffered from the "not designed in the US" syndrome, even if it was the main rifle used in WW1 by the US.