Biased here! But the only option on their list of alternatives that are drop-in replacements for the Kiva System with great updates for next-gen system seems like Otto (http://www.ottomotors.com/vehicles). Great improvement by removing the need for infrastructure changes (all cartography is onboard and centrally maintained).
They're just targeting different markets. Otto is largely targeting manufacturing, Locus is targeting e-commerce and fulfillment more. The morphology of the robots follows from that.
RoboCV (http://robocv.com/), a pretty good Russian company is missing from the list. These are the same guys who were participants of Google Lunar X Prize but aborted midway due to lack of funding.
