When I first got my TI-83+ from Brother, the first app I ran was MirageOS 1.2. Ever since then I have used Mirage, even though it crashed multiple times and "forgot" some programs. Even though I now use DoorsCS I still keep Mirage on my Calc, just in case.
Graphics: 10/10, the simple graphics were all it needed.
Speed: 8/10, when it first starts up and usually takes a while if you have a lot of programs.
Usability: 10/10, Simple controls and lots of features.
Stability: 6/10, It sometimes crashed and kept "forgetting" I had Mario.
Overall: 8.5/10 Simple and Easy, it gets the job done usually.