Crucial M4 VS Sandisk?

I've been looking at SSD and decided to go with a Crucial M4 thanks to their great reliabilty,but then I stumbled across a Sandisk SSD that was twice the storage for a bit less cost and seemingly better performance.

I couldnt find what controller the Sandisk used as I know sandforce controllers are unreliable and I also wonderd why this SSD was so cheap for the amount of storage as it out performs the M4.

So what I asking is whether its worth going for the Sandisk SSD for speed or the M4 for reliability

P.S. Also when looking oon Ebuyer I found that the M4 and the M4 slim seem to have different read/write speeds,the slim being 45K/20K IOPS and the normal M4 being 40K/20K IOPS,is this just a typo or is there really a performance difference?

M4: http://www.ebuyer.com/264770-crucial-64gb-m4-ssd-ct064m...
M4 Slim: http://www.ebuyer.com/342457-crucial-64gb-m4-ssd-slim-c...
Sandisk SSD: http://www.ebuyer.com/387080-sandisk-128gb-ssd-sdssdp-1...