For the brand I will get the intel 520, but for the real usage I will get the M4, 1) both are good and the M4 is $50 cheaper, 2) you will not notice the difference between them in the real usage but you see the difference in the benchmark.
For gaming you will notice no difference between any decent SSD. I would also consider the Samsung 840.
I have the Crucial M4 256GB model and its great. If you go this route when you get it make sure it has the 040H firmware as it fixes some bugs and includes performance increases from prior firmware updates.
"Performance is typically characterized in one of three
ways: input/output operations per second (IOPS),
throughput in megabytes per second (MB/s), or with a
composite benchmark that gives unitless results.
The empirical data referenced in this paper was taken
from a sample SSD from a well known manufacturer.
Although the exact shape and amplitude of the
resultant performance curves may differ among SSDs,
most drives currently in the market will experience
similar behavior. As the drive fills, performance changes
nonlinearly. If the measurement period is sufficiently
long, the device will exhibit one or more intermediate
performance states observed during the measurement