As a Cat Dealer Principal this discussion is very intresting to me because there are so many misconceptions.
First off, the new Nissan forklift is not the same at all. The early stages of the product were developed together so the styling is similar. The engine and transmission are the same and that is it. After these two parts, Nissan took a cost cutting approach and MCFA lived up to the Cat name. Some major differences are: the stronger mast in the Cat, one piece headguard on the Cat, and the software that controls the engine.
The mast deflection in the Nissan is the worst in the industry; and all the Mit/Cat masts are made in Houston with the trucks - the only LiftTech mast that is put on a Cat truck is the quad mast for counterbalanced and the mast for the Narrow Isle Reach truck (NR3000-NR4500). (Frame-Rocla & Mast-LiftTech then they are assembled in Houston).

To clarify some of the other statements: MHI still makes the 4G64 engine, a majority of the MCFA employees are old Cat guys, there is no bad blood between Cat, Mit, or MCFA, and the 8000-11000 Nissan truck is built in Houston by MCFA for Nissan.