You don't think Infinidat is? Much the same original development team (those who got out of IBM as soon as they could, including the boss), kept and improved on the good bits and ditched the bad bits.
The Tintri comparison has some validity. It's a current-generation system, although they still use dual-controllers, something which XIV was one of the first to ditch for something more reliable.
Cleversafe's the only new thing that IBM really has, now that XIV has been beaten at its own game. DS8000 and Storwize are both 1990s architectures struggling to keep up. Add to that a bunch of staff who no longer give a shit and it's hardly an appealing proposition.