Violin is top for now...
Chris, I just saw a Gartner Chart (June 2013) that has a different order to what you have posted, you may want to visit it, the list above is wrong.
Outside of that, sure Violin is top for now, however they just got IPO'd and I would still consider them a "start-up" which means they could get sold off at anytime. Would you trust your enterprise systems to rely on a vendor who may be there or maybe not? They also don't have World Wide Support and there is a scaling issue with their boxes, aka very niche.
IMO, all of these fly by night flash storage companies are going to get out paced by the larger vendors, EMC, NetApp, IBM, etc... All of these new players in the field also have various downsides to their products varying from scaling issues, to support, to not being able to do simple basic storage functions like replication.
The NetApp EF540 is considered an "IOPs Vampire", is scalable, offers basic storage functions like replication, snapshots, thinprovisioning, etc. NetApp may be lower on the list at the moment however the next few quarters should show a change in market share. Mark my words.
and all those who left NetApp to go to Pure are in for a rude awakening when the investors at the top decide to sell off the company.