Why I simply prefer NCO before recon is because of the extra gear; the choice between SMG and rifle, extra bandages, sidearm (pistol), and if you're playing Italian you get some granade too. If you pick the bolt-action rifle as a squadleader the sidearm comes more handy in close combat.
I barely would pick the SMG kit as a squadleader even though it has granades. The squadmember should be able to have SMG kit before the squadleader since they can't have the NCO kit unless they pick it up in the battlefield. Therefore because the SMG kit is limited kit every taken SMG kit by the squadleader is a lost kit from the squadmember in my opinion.
Speaking of uniform I don't think about it while taking NCO kit. If we think about how easy it is to recognize the squadleader from the squadmember especially in North-Africa (the hat the German and British squadleaders are wearing) so I wouldn't consider the uniform as one of the reasons to pick NCO kit.