Rincon is 680CC, lots more power. Transmission is a three speed hydraulic automatic. Gearing is terrible for anything other than trail riding.
Rubicon...I assume you mean new? DCT transmission has gears, and a computer shifts it for you. Also has a diff lock and low range. Much more versatile bike.
If you want only a trail rider with lots of power, get the Rincon. If you want to use it for ANYTHING else, get the Rubicon.