We have actually gone to Sig 9mm. I hate them - thought there was nothing worse than the Baretta then found this. I have a biased opinion though since the Sig's are completely un-left-handed and have too many damn buttons and levers. Everyone except us leftys like them better as they are more accurate.
I have not actually shot an M4 yet. We still have the M16-A2s. Compared to that....I liked it a lot! I only got to shoot off a couple clips at the very end, so did not have nearly as much time as I would have liked to play with it and figure things out, so can't make too many comparisons. Other than it being FUN. Lol.
Since I was at a range that theoretically wanted you using 5 rounds/clip, mag capacity was not a big issue. Although since the guy I was shooting with is law enforcement, he did have the high capacity clips.
Michelle - Proud DR Rockette S: 28JUL07, D'd: 29OCT09 http://tinyurl.com/27j9qo2