The Lee Enfield is a more reliable Battle Rifle than the Mauser.
It also has a FASTER action, Better Sights, and has greater firepower. Also the No.4 Mk.1 Lee Enfield allows the shooter to compensate for a change in head space by simply screwing on a longer bolt head. Whereas with the Mauser you would need a gunsmith to unscrew the barrel cut and rethread it and screw it back on if the head space becomes excessive..not so on the No.4 Mk. 1 Enfield!
The Enfield's chamber was made longer due to the fact that the British Empire had multiple arsenals over the world, (Ishapore, India; Australia, etc.) The chambers needed to be large due to differences in MkVII ammo dimensions from different arsenals.
This had the pleasant side effect of making the Enfield more reliable when Dirty than the Mauser.
The No.4 Mk1 Enfield has a hole drilled into the side of the receiver ring to allow gas from a burst case to escape.
Unlike the Mauser 98, the Enfield Cocks on Closing, this allows the rifleman to exert all of his energy in extracting the spent round, it also allows the rifleman to slam home a new round during rapid fire.
The No4 Mk.1 Enfield has a butt trap for an oiler and a pull through cleaning gear.
The .303 service round is the Mk VII ammo which has a 174 grain FMJ bullet with an aluminum insert. The Aluminum insert causes the center of gravity to shift to a large extent to the rear making the bullet just barely stable while in flight, once it hits a target it starts to tumble like a buzz saw causing horrific wounds.
Ballistically the .303 Brit has 10 percent less energy than the .308 round.
If you want a HUNTING rifle..then by all means get the Mauser..on the other hand if you want a rifle to FIGHT with, then you are better off with the Enfield.