Not trying to be a jerk...
But use the search function. Every 2 months, someone asks about the M&P 15 series, and the same responses get put up.
1. Works great for about 95% of what most people would use it for, probably even higher than that.
2. Good value. Not great, but good.
3. Might not have all the boxes checked off on The Chart, but see #1
4. Good starter platform, either for future building, or for learning.
Here.
Added after SA80Dan's post: I hope I don't come off as a snob. I have both a Colt 6920 and a -15T. I like my M&P15T. I recently converted it into an SBR. See #4.