You get what you pay for.
The cheaper one may have the same features, but the more expensive one will likely have better/more stitching, more comfortable, more durable, heavier duty straps and fabric, etc
Be absolutely sure you want one with built in mag pouches though, cause once you buy that one, your stuck with M4 mag guns, and you don't have the ability to move the pouches if you end up not liking where they are placed.
I may not have been playing airsoft that long, but from what I've seen, I wouldn't recommend one with permanent mag pouches. Although you may buy it and may fall in love with it, everybody is different.
This is what I use:
http://www.cheaperthandirt.com/MOLLE365-1.html It's Condor (OE Tech to ASGI)