SSDs have to have their place. In SATA 2 mode, you will boot faster, and transfers will saturate the bandwidth faster, but you will not see much difference in day to day activities. In SATA 3 mode you will be better off, just faster than SATA 2, but you can not just do everything like you always have done. You need a secondary platter drive to store DATA on or you will degrade your drive fast.
Personally, unless you are using it in a laptop (I have not read all 3 pages yet, so not completely sure) for heat reasons, or for battery reasons, I would stick to a HDD. The differences are not worth the cost if you are not fully committed to it.