10mm. A Glock, 10mm, is arguably the most powerful handgun you can own. 5 or 6 shots of .44 mag is definitely not as good as 15 rounds of 10mm.
I have a Desert Eagle .44 magnum with 10 round magazine. I think that'll beat a 10mm glock. And, it can be used as a boat anchor.
Seriously, I'd vote for a 10mm Glock for an outdoor handgun in the conditions described.