Re: What is there to free ?
What I saw specifically was IBM shops looking for a solution that IBM couldn't provide themselves - the N-series stuff is way ahead of the DS-series stuff on features and functionality (and was often put in front of existing DS storage to extend ONTAP features to the legacy arrays). IBM would pitch N-series to those customers to keep them in the IBM camp.
The downside for IBM is that IBM would often bring the first FAS into an environment, but once the customer saw the number of things they were missing as part of being an IBM customer rather than a NetApp customer, NetApp would sell the subsequent arrays (IBM didn't certify many versions of ONTAP and was often 6 months behind on software updates, as well products which became free for NetApp users were a pain to get a hold of for IBM customers, plus the My AutoSupport site was not available to IBM customers - big let-down, and further, the support was terrible off-hours).
I could see the deal being lucrative for IBM in the beginning, being able to offer a scalable, high-performance multi-protocol storage array without losing customers to competitors, but once those customers started turning to NetApp for future purchases the writing was on the wall for the OEM deal (NetApp specifically supported SnapMirror from N-series to FAS for data migration and provided the licensing free of charge for that purpose).
I don't know how the Unified offering works out for Storwize customers but I've heard mostly good things on the block side (especially for FCP, with a few odd comments about poor iSCSI performance under VMware but that was from a P4000 pusher).