Being able to show my students exactly what they need to do to pull them up to their desired grade is fantastic. Knowing instantly what a student's work has done for them and showing the student is a great motivator. Showing parents who complain about their student's grades is great too, there's no ambiguity, the numbers are there. The weighting and bonus grades allow some flexibility to reward students who make that extra effort.
The custom grade scale is an absolute nightmare. My board (and indeed education ministry) uses Levels, not letter grades. 1-, 1, 1+ etc. Because Thinkwave takes the average of the gap between the minimum grade needed to achieve a level and the minimum of the next one, to get a fair number takes a lot of math work, which hurts this English teacher's brain. Example. 3+ should be worth about 77.5. In order to get that, I have to make the minimum grade for it 76 and the max 80. When a student fails I don't want to necessarily just give a 0, sometimes 10 or 20% on the major assignment can make a huge difference. If I want to make a grade of 20, I need to create a grade called 20 with a minimum of twenty and then create a blank grade (___) with a grade of 20.000001. Doing this for 10, 20, 30, 40 and 45 is rather obnoxious and takes up a lot of room in the drop down menu.
The same goes when you try and make a check grade. If a 0 is entered it actually gives the student a 25 because it's halfway between 0 and the next grade, a 50. Took me a while to figure out that you need to enter the grade as incomplete to get a 0. Missing discounts the grade from the averaging entirely but makes you aware it is missing, and excused does the same. Kinda strange. Be nice if there was some documentation to go with the custom grading so I didn't have to figure this all out via trial and error.