Four star review for a five star product - Nathan VaporZach Vest 2.5L - Men's

This is the first hydration vest that I have owned, and that is my only reason for giving it four stars. I assume that there are more advanced technologies, and better products out there, but I have no basis for comparison. I have been extremely happy with the fit (no bounce), and functionality of this vest. On average I run 30 miles a week. I have completed two runs in this vest, 12 and 15 mile runs, and I haven't had a single problem. The straws and the bite valves were a must for me when I was shopping, and they function perfectly. This vest comes equipped to hold 24oz of water, and I've cariied up to 42oz plus snacks. I put an 18oz soft flask in the larger pocket on the upper back. One thing that concerned me, but didn't turn out to be a problem was inconsistency between the Nathan website, and the product regarding sizing. Based on Nathan's recommendation of 37" to 39" (chest circumference) I orderd a small. Upon receiving the vest, the tag indicated the small size was 35" to 37" or maybe 36" to 37". The point is, I would've order a medium. Turns out that the small fits, probably could've sized up. I'm 6' 0" and 174 lbs.