Hi 阿超 (I wasn't sure if I could actually cut and paste that, but I knew my keyboard wasn't going to let me type it)
That is definitely a loaded question, and there are a couple of different ways you could look at it. From an engineering and technology perspective I think the biggest changes are to the backend of the array with a shift away from FC drives to SAS and NL-SAS as the workhorse drive technologies. In the end this doesn't really make a huge difference to the end user though. From a customer/end-user perspective I suppose the shift from non-integrated block and file architectures to a much more integrated/unified design is a huge shift, but won't actually impact all customers. You can still use a VNX as a block only array and it really isn't going to be much different from using a CLARiiON.
In the end I have to say that for most users there isn't really a game-changing, life-altering difference between CLARiiON and VNX. I don't mean that as a slight to the engineers that bring us this wonderful new technology, but this is answering the questions from a purely practical average end user's perspective.
If you are moving up from an older model CLARiiON then you can gain functionality like Virtual Provisioning and FAST VP as well as FAST Cache capabilities and a some other bells and whistles, but really, if it were not for the hardware backend changes this would almost qualify as a "CX5" rather than a new product line. That's just my take on it though.
To keep that answer in perspective I will say that if you were asking me the different between a Honda Civic and a Porsche, I would tell you that for the average driver on average city roads with no special requirements, there isn't a whole lot of practical difference. That doesn't mean the Porsche isn't worth the extra money and can handle things that the Civic can't, but that really doesn't affect the average end user.