Not hating on airsoft, I played a lot of both airsoft and paintball before I enlisted and I use airsoft as a training aid for my guys but as previously mentioned understand that it's not really the target audience of this forum so you might catch some flak from time to time. Some people look down on it but I've gotten some really good training from it so rock on.
That being said I vote for the JPC 2.0 or even a JPC 1.0. You can't beat their simplicity, quality and value and after wearing one every other plate carrier I try feels unnecessary large and suffocating. If you plan on actually running plates I'd get training plates for your airsoft matches so you don't bang up your real plates. Also, if you are going to get real plates read through the body armor section on this website to learn about what kind of armor you should get (hint, it's not steel).
Check out the Arbor Arms cummerbund with First Spear tubes, little bit lower profile than the First Spear cummerbund. You could also have a JPC cummerbund modded to use the tubes which would be my reccomendation but I understand that cost is a concern.