Tempo synchronization has been available via midi since the 80s, (You just have to match the time signatures) the answer is yes.
The one thing you have to remember is that the Genos & Modx are opposites in that everything is done for you on the Genos (Just like any arranger) whereas the Modx gives you the basics and you then mould it to your requirements. (Hence the superior real time control of a synth/workstation compared to the limited controls of an arranger)
It is best to go out and try them to see if they suit what you want, as the operation is significantly different. (Personally with a Genos (And assuming you want to stay with Yamaha) I would save some more money and go with the Montage)

Bill