Basically it says that, IF you can swing it you should get a SATA III SSD. It depends on which SSD you get but, chances are a SATA III SSD will be able to saturate the SATA II connection better than a SATA II SSD will.
Also, in most of the tests the samsung 830 series SSD's do the best, followed by the Crucial m4.
If reliability and stability is a major concern, then I recommend Samsung. Samsung was awarded contracts to supply Dell, Sony, Lenovo, Apple and other off the shelf brands with OEM versions of their 470 Series SATA 2 3Gb/s ssd's. Eventually the 470's were released for retail sale to consumers. There have been no major issues reported. The 470 has an absolutely stellar record.
Then Samsung released their 830 Series SATA 3 6Gb/s ssd's as successors to the 470. The first ones were OEM versions for Dell and the other off the shelf brands followed by release of retail versions for consumers. The ssd's are Samsung's own design with their own components and firmware. It looks like Samsung got it right again.