The specs look pretty good, reviewers on Amazon are saying they've got it to work on 2011 MBP's, so that's good. Vertex 3's were said to have some issues, hopefully these were fixed with the new version.
Unless you're going to be doing a lot of very disk intensive work with you, you may not notice any difference in day to day use with the M4. The CW is to get the best deal possible on any reputable SSD that works with your type of sata connection.
Speed wise the Vertex 4 is faster, but you probably won't really notice a difference between the two in regular day-to-day use. The issue will likely be reliability. The M4 is generally considered to be one of the most reliable SSDs. I'm not sure on the reliability of the Vertex 4. That would be my biggest concern. Amazon says it comes with a 5 year warranty, which is great, but it's still a pain if your drive fails and you need to get it replaced. Also keep in mind that the M4 can do firmware updates directly from the Mac. With the Vertex, you'll need access to a Windows machine if you need to update the firmware. That's not a big deal to some, but I don't have easy access to a Windows machine so it was important to me.