Your dealer may have been steerring you to the kubota.. because that is what he had sitting taking up space.
Don't be afraid of the tc18.. a nice cast iron frame...
And yes.. the tc18 is a bit bigger tractor sizewise than the bx kubota I believe.
I'm partial to blue, though because the kubota dealers down here think there units are $GOLD$ instead of orange... same with J$O$H$N$D$E$E$R$.
In north central florida where I live, the NH dealer, and the MF dealer are the better price deals, with the MF dealer being slightly lower. Though in recent years, their tractors have gotten lighter than i like.. they make a 25 hp model that is physically smaller than a tc18... Since a tractor's work comes from traction.. which is heavilly reliant on weight / hp.. when you cut the weight and up the horse power seems like you get a unit that is good at spinning tires...
again just my .02$.. I like MF.. good solid time tested technology. As for NH.. I'm biased since I own a couple fords and a NH..
Soundguy