Yes I know of the default AHCI drivers, and they will work. In fact I’ve used them for trouble-shooting.
If you’re happy with them, then by all means use them.
RST drivers are recommended by the motherboard manufacturers, and by most SSD manufacturers.
Also, the standard AHCI drivers can’t TRIM a file that is over 2GB in size.
They also don’t support the full feature set of P55 and P67/Z68/H67.
While performance gains can be marginal on some SSDs, on others, such as the OCZ Vertex 3, the performance gain by using RST is quite substantial, especially with higher queue depths.