Summary: BTW, this happened to both the drives. One followed 2 months after.
Pros: They worked for almost two years.
Cons: There is a known issues with this model that after how many hundreds or thousands of hours (I forget which), the garbage collector no longer works and what happens is you can start Windows or whatever OS you are using, but randomly (30 mins, 1 hour, whatever), the drive will no longer be recogniz...
Summary: I hope SSD technology is better and more reliable a couple years on.
Pros: I loved it initially. Increased boot-up with Windows 7. I bought this SSD to replace my WD Raptor which died.
Cons: Tried to boot up computer last week and got the blue screen of death. Then the bios wouldn't recognized the drive. I tried the Crucial instructions and bios now sees drive, but Windows 7 cannot install on the drive. At this point I consider it a lost cause and ordered a new SSD from a different m...
Cons: This SSD has only lasted me a little over a year before it started to fail. Speed tests in windows index factor have decreased 2 points over the last year. It also will not load in bios more often.
Summary: I have submitted the RMA request with crucial since they have a 3 year warranty. We'll see how that goes.
Pros: Fast and inexpensive.
Cons: Life span is pretty terrible. I had a problem with it before and switching it to the SATA 2 port seemed to get it worked out but now it appears to be toast. Purchased 12/13/2012 -> stone dead today 09/19/14
Summary: I've seen this HDD vanish from boot list and require some intense fiddling with DOS utilities as well as disconnecting/reconnecting of SATA cables. It's a massive amount of headache and stress for the few seconds of boot time it shaves off regularly.
Pros: During sales, fairly cheap for its effectiveness. Otherwise massively overpriced, however. That's all.
Cons: Incredibly vulnerable to vanishing from BIOS and boot list during any sudden power loss (shutdown from overheating, power outage/surge, etc). While this is a known issue for all SSDs, the Crucial M4 is known for having this issue more so than almost any other I've seen.