The M4 is a nicely balanced weapon, in my opinion it's best for medium range targets. The G36 is good for close range and long range targets, its powerful shots are deadly at close range and its high magnification scope is effective at long range. The only thing that's keeping the G36 from being perfect is its messy recoil, it can really throw off your aim if you shoot fully auto at medium range. The M4 is very steady and has low recoil, making it very effective at medium range. But it can sometimes seem weak against other weapons such as the G36 and the AK-47, as well as the SCAR, which deals more damage and also shoots faster than the M4. The lack of a high magnification scope available prevents the M4 from being very effective at long range, its moderate fire rate and damage makes it not the best choice for close quarter engagements. But which weapon is better depends alot on the user, both the M4 and the G36 have very different characteristics, so it's up to the way they're used that'll determine which is better.