Performance is much better when a solid state drive is used as a Windows 7 boot drive and to store software applications.
Intel's SRT caching technology was designed for buyers who cannot justify or afford the cost of a larger capacity solid-state drive. According to Intel, the original idea was that for about $100.00 a user could purchase a small capacity ssd of about 20GB and use it as a cache to improve hard disk drive performance. The actual improvement could not compare to a stand alone ssd. Intel also tested different capacities all the way up to 512GB and concluded 64GB was the point of diminishing return. It made more sense to use a 64GB ssd as a boot drive that also contained software programs. Intel was hoping that if business clients saw an increase in performance, then they would be induced to purchase larger capacity ssd's.
Here is a link to the instructions published by Intel:
http://download.intel.com/support/motherboards/desktop/dz68db/sb/intel_smart_response_technology_user_guide.pdf
Here is a link to Intel support for SRT:
http://www.intel.com/p/en_US/support/highlights/chpsts/imsm
Here is a link explaining SRT and how to set it up:
http://www.hardwaresecrets.com/article/Intel-Smart-Response-Technology-Explained/1292
All of the SATA III 6Gb/s ssd's you mentioned are good drives. The Crucial C300 is a very popular drive. The Crucial m4 is supposed to be a new and improved version of the C300.