Why is this SSD more than this one when the size and transfer rate are higher?
Because Intel knows they can sell their drives at a higher prices.
Because Intel make a big deal of thoroughly testing all their drives and charge more for it. They do have a bulletproof reliability record though.
In any case both of those are Sandforce based SSDs which I would avoid. Get a Marvell or Samsung controller based one instead.
What's wrong with Sandforce?
Past reliability problems (mainly from OCZ) and not great performance with incompressible data. The sequential read/writes might seem impressive but what's far more important is the 4K random read/writes.
In real world usage you will probably never notice the difference but given that the Crucial m4/Samsung 830 are around the same price as Sandforce drives so I'd go for those instead.
You know there aren't many alternatives to Sandforce.
By far the most popular drive I see on forums is the Crucial m4. Sure there's a lot more Sandforce models than Marvell/Samsung/Indilinx but that doesn't mean you should go for Sandforce, especially when the "alternative" is superior and more popular. That's like saying there's tons of Android phones out there but there's only one alternative (iPhone) therefore I must go for Android.
Bit of a contradiction don't ya think?
Anyway if you knew the first thing about Sandforce drive issues, half the problems were *caused* by Intel not following the SATA3 spec. They only released their own Sandforce drives once the problems with their own SATA3 drivers and the Sandforce firmware were ironed out which required cooperating fixes on both components so it was actually a hand-in-hand issue.
But it is true about Sandforce and incompressible data. That is a shortfall and the SF-2xxx chips now have IOPS specs below the new gen drives (which is directly proportional to random 4kB read/write).
Edit: To add to the OPs question, Intel also have custom Sandforce firmware. They would have much better capability to tune the SF firmware and RST drivers to work nicely together that others obviously wouldn't be able to do.