I perfer velcro, it worked fine on me. You can hinge if you want, but I didn't think it'd be worth it. Velcro can be easily modified, putting a permanent hinge on limits what you could do in the future if you choose to modify them.
if you were doing jango gauntlets, then absolutley do the hinges, but if youre doing fett, I'd go with the clamshell & velcro method. Its accurate to the original, and works pretty well. If you end up getting bit by the accuracy bug later on down the line, (as many of us do,) you may kick yourself for assembling your gauntlets a different way. Up to you bud
i found that using the velcro method has been unfriendly on my paint. flexing the plastic to open/close the velcro has caused the paint to crack and peel in places that i didn't want it peeling. i've had to touch them up several times because of that.