Why did Chrome remove the Cubic Inches from the specs on their new site? Other than that, the new site is great.
And the Kirov also differs in the fact that it has compression straps, but they are different from those on the Warsaw and Backbone. The ones on the Warsaw and Backbone can be used to strap large parcels under the front flap.
(I have a Backbone, btw, and haven't been in a store that stocks Kirovs or Warsaws so all this is based off of the pictures on Chrome's site.)

If all you need is a lunch, hat, hoodie, and bike stuff (pump, patch kit, tube, blinky) you should check out the Dually. I want one for days that I don't need my para-sail (aka Backbone).
If you ever need to carry a laptop and have a 13" Macbook or thereabouts it should fit. I have a 15" and I don't know if it would fit in the Dually, but it fits in a Ranchero.