Hey Deane, i owned the T5,but the difference is not so big as from the T4,lot's of T5 is in the Genos,what you get witch the Genos?a couple of new styles,Dsp's(very good)new presetvoices and ofcource,a new design,but Ketron is more advanced in technique,and it's easy to handle,and it is fast,and again,drums/percussion/bass/live audioguitars,it's the best you can get.