Permitted the unlikely "luxury" of picking my sidearm prior to going in harm's way, especially in a dusty, sandy environment with little in the way of repair shops, I'd pick the Glock 17/19.
Routine cleaning and maintenance can be satisfied with some pilfered motor oil, a small piece of cotton cloth (T-shirt) and five inches of improvised cleaning rod.
If it gets really filthy and needs a complete detail strip and cleaning to set things right or an "on the spot" repair, I can accomplish either with nothing more than a 3mm Hex wrench and a small parts "repair kit" that'll fit in a small shirt pocket, consisiting of a few crucial small parts (three trigger springs, one firing pin and three springs, 3 sets of firing pin spring cups, three spacer sleeves, two complete guide rod units, two firing pin safeties w/springs and an entire extractor/plunger assembly) in under five minutes.
The "expedient" capability to maintain, service and repair the Glock 17/19 with little more than 5 minutes, some oil and a 3mm punch is where the Glock shines, the "other choices" not so much...