I have both, and vastly prefer the P-08 Luger. Mine is a 1941 Mauser, and it has been 100% reliable with all ammo that I have used. This includes bulk FMJ, JHP (yes it feeds all hollow point SD ammo perfectly), and my reloads including truncated cone.
My Luger is more accurate than my P-38, and has a much better trigger. As German officers carried a pistol as a sign of rank, and ego, I am certain they preferred the Luger over the more commonly machined P-38.