I've always went Im. Never had any issues. Once when I went into my glute, i always inject slowly. A good 30 to 60 seconds and never have any soreness, bruising lumps etc... no issues. The one time with my glute, I guess I shifted the angle a little bit over the course of the injection. Well shifted a lot. Didn't realize how much and it felt like a charley horse for a day or 2. But thats the only pain ive experienced.
Stephano, you're saying that IM can damage the muscle? How so, just the repeated trauma of sticking a needle into the muscle?