Note: this question and answer assume an end-stage setup with the stage set-up in front of lower level Section 112.

The main difference between section 104 and the 200 level side sections is the angle to the stage and your resulting view. From section 104, your seats will point towards stage right, and you will be able to see all the action on the stage with minimal head-turning.

Section 104 Seat View
The view from Section 104 for an end-stage concert at Madison Square Garden in December 2014

In the 200 level side sections, you are sitting higher up and your seats will naturally be looking directly across the floor at the opposite side of the Garden. For sections farther away from the stage, this will result in having to turn your head to see the stage. For other sections, like 212 and 223, this won't be an issue and you'll have a very good view.

Overall, tickets in Section 104 will be better than most of the 200 level, except the front rows of the side sections closest to the stage.

Section 212 Seat View
The view from Section 212 is among the best on the 200 level