Also voted R10, same reason as what Lee said. When deploying internal SSD in a SVC cluster and ordering 2 drives per node, it makes sense to create RAID1 (across nodes) or RAID 10.
I answered RAID 10, but not for the reason you offered.
A lot of customers are only adding 2/4 SSDs as that's all that is required to deliver the performance they need (due to Easy Tier's efficient use of SSD for only "hot data" extents).
For that reason, they're running RAID 1 or RAID 10 due to quantity, not to maximise write performance (although that's a nice benefit on top for the hottest data).