When grading in SpeedGrader, it is necessary to put the cursor in the numerical grade box, enter a number, then move the cursor over to the "arrow" to advance to the next student. So, it takes two precise movements of the mouse to put a grade in for a single student. Sometimes it is not necessary to leave any additional comments for students after the online submission is reviewed by me. All that is needed is a grade to be entered and go on to the next student's submission.
So, my suggestion is two-fold:
1. When SpeedGrader advances to the next student (or opens in the first place), the cursor is already automatically in the numerical grade box.
2. If all that is necessary is the input of a number grade, then once the number is in and you hit the Enter key, SpeedGrader auto advances to the next student. And the process continues.
This would save ~5 seconds per grade (add that up over the course of a year or career), loads of frustration, and significant petty decision fatigue.