Up to you. My full spirit fighter was a lot more fun than my full endurance fighter though. I went full endurance thinking it would help me tank more effectively and whatnot, it's okay, though not noticeably different. If you want to just tank for parties in CP, then full endurance is for you. That spirit/endurance build is good for improving a fighters terrible soloing capability through a slight boost in damage. Getting a higher critical rate on a fighter isn't the best choice when grinding on the upper level monsters (like killing Harkans with a party at level 3x), because you'll miss them a third of the time. It makes for decent solo against green/yellow monsters though.

well, i have +17 spr. and with good weapons i crit aoe, (6 monsters) about 5 or 6 times. but the sp isnt worth it cuz only mages use magic (maybe archers)
i put some in end and 1 in dex and rest in int.

but im not sure, it's ur choice