Actually, both in 2.3 and 2.4 I found MG to be second best initial weapon (after GL). It remains in my arsenal even now, after researching coilgun, all lasers and plasma weaponry. It might seem heavy at first, but good soldier got enough TU to do one step around corner, send a full auto into enemy and step back-31 TU if crouched in previous turn. On standard diff, it is one of few weapons that got power to take down Ortnok on medium armor in one turn.
It is unsuitable for use in buildings and UFOs later, but its good for first round shootouts that often happen at crashed UFOs and some maps..