The vast majority of road-side mowers I see are New Holland. However, for the non-contracted portion of interstate mowing my state does (NH), they have been buying Kubota for 10 years now.
Kubota sells the most compact tractors in the US. In my opinion, the Deere compacts aren't that great, most are not made in the USA, and cost the most. Dealer support is probably the best though. I hate how all the independent JD dealers are gone now, and they are all some giant dealer (United Turf and Ag up here in New England).
I've also noticed Kubota is partnered with Versatile tractor of Canada now, so the Kubota M8 - really just a customized Versatile Nemesis - can be had with a 200HP 6.7L Cummins and a ZF made Powershift or a Kubota made KVT / CVT transmission. Kubota, through its purchase of Great Plains, is offering big tillage equipment and high quality hay equipment with its purchase of Kverneland, but needs a bigger tractor. The rumor is that Kubota will likely purchase Versatile in order to have exclusive access to its larger tractors, and the Cummins engines will be replaced with Kubota-made diesels and transmissions.