When I was in high school this grading scale was used for our honors classes. Yes our classes were more advanced and our grading scale was harder but we were up to it. Also we received weighted grades for these honors classes...so an A in an honors class counted as a 5 in a 4 point scale. With that in mind I thought it was appropriate for us to have to reach the highest standard possible.
I think that going on a percentage basis would be the only way to accurately reflect achievement. Percentages are easy to compare etc when kids get older and are looking at applying to colleges.
I don't intrinsically have an issue with earning grades but then I was always a straight A student who was very competitive by nature. I was motivated by the high standards etc. After teaching high school at a school in which the children were an "at risk" population...I still didn't have a problem with assigning grades because I did not come across many kids that failed and actually put forth an effort. I failed many kids but most of them were frequently truant, discipline problems (gangs etc) or just did not turn in homework...sometimes the lack of work turned was defiant. Any teacher I worked with was almost always willing to work with a kid who was willing to work but didn't feel bad about failing a kid who did nothing. Let me say that I was never told about a kid having an IEP or 504 plan that I didn't follow and I was one of those teachers that would go an extra mile when I could to help the kids.
My trouble is that my kid doesn't fit into this system well and I am conflicted by this. I don't want to send the message that grades are unimportant...because they do have some weight later in life. I don't want her to think Mommy and Daddy don't care how well she does in school yet I don't want her to be discouraged by grades.