Well, the Crucial M4 is known to be one of the most reliable drives out there. The write speeds specified are the fastest. This does not mean that the drive will maintain that speed when writing. I wouldn't look solely at the max read and write speeds as in real life usage scenarios, most of the drives are pretty much identical.
As for the drive you've suggested, I don't really have much experience or have read much into Pny drives so I can't really recommend them. I have a Force 3 and an M4, where the M4 has been flawless since I've had it. I've had a number of issues with my Force 3 drive, hence why I recommended the M4 and not the Force 3.