Consider that an 2.5-in. Intel X25-M consumer SSD with 160GB of capacity sells for about $400 on online retail sites. Then consider that the most recent wave of economy SSDs have been low-capacity models, such as Intel's X25-V, which has 40GB and retails for $120. A quick comparison makes the SSD 310's value clear.
That said, I'm still a big proponent of Seagate's latest hybrid drive -- the Momentus XT -- when it comes to overall value for today's laptops. You can purchase a 250GB capacity model for $113 and experience a big kick in performance.
But I can clearly see the day when a dual-drive laptop or netbook -- or even an iPad -- would greatly benefit from an mSATA SSD, particularly if you want to combine it with a massive 1TB, 2TB or 3TB hard disk drive.