It failed. It just produced a level of IT complexity irrelevant to mathematics and little further development of mathematical thinking. The proposed gains in graphing did not materialise (due to the size of screen and accuracy of the LCD) and the CAS element was nifty but questions it could be used for were often implemented in non calculator sections anyway and calculator section questions often have to avoid questions that would otherwise demonstrate understanding but can be answered without knowledge by the calculator. In many cases it caused issues for examiners to ensure that problems were not trivialised by button pushing.
The level of skill with the calculator by each teacher has the potential to differentiate between students in classes and schools more so than their individual mathematical aptitude (or teacher knowledge), particularly in Applications and Methods as teachers in rotations develop their skill with the device. It was never the aim to have the calculator impact on the teaching quality received by students, but as each new teacher is introduced into a course, it has increasing potential to do so, more than without CAS.
I don't think it has aided algebraic ability either, with students not always receiving the algebraic grounding developed through solving complex equations. CAS has the potential to trivialise this process, and can limit the development of fluency, particularly where texts do not state where it should be used (or where students use CAS where they shouldn't). The counterargument is that this is dependent on the skill of the teacher, and I don't discount this, but it is just another factor that impacts on teaching with limited, if any, benefit. It certainly hasn't given access to maths at a higher level than ever before, one only has to look at declining engagement numbers and the relative farce that is the current applications course. This though, is just my opinion.
This is causing some students to reconsider doing higher mathematics, or worse still attempting to do it without the calculator, particularly if it is lost or broken (and not covered by the one year warranty).
I've just had an email from Abacus that they are getting a 15% increase in cost next year. At $270+ it is getting pretty close to the cost of a reasonable tablet, with a larger screen, multi-purpose, similar software and enough battery life to get through a day. Sure, standardising it for exams would be difficult but considering it as a thought exercise it makes you think.
Universities and other learning areas never took the CAS calculator into their courses making it irrelevant post schooling.
If it is costly, is not providing the benefits suggested in senior school classes and has little relevance post schooling, would we not be better dropping it as a failed experiment. I remember reading a post from Charlie Watson (Calculator guru and all round nice guy) proposing to discontinue it. I do agree and would like to see a pure math subject returned where the skill in developing mathematical knowledge through a simple text and a teacher was the primary objective rather than driving the use of a mediocre device with limited applications beyond high school.