I am quite pleased with this version. It is stable, and functional. I don't think I should mark it down because the Win version is better. I feel fortunate that there is a Mac version at all. This version has an English interface, which, as far as I can tell, is not possible on the current iOS version.

I just upgraded to the 3.9 version from the Apple Store. I am completely satisfied with the way they handled what is an awkward situation. It strikes me as fair and reasonable. In fact, I bought just before 3.0, and got 3.0 for free. Now I am buying just before 4.0. The number of people who view the situation as a good deal will vastly outweigh the number who are going to be upset, and it is the upset ones who make the most noise. I suspect that the AgileBits folks will be as gracious as they were to Dualie, and elsewhere.

Remember, you are under no obligation to upgrade, and 3.8 works extremely well.

1Password is awesome.

the download still says version 1.1

This is a terrific teaching and learning tool for intro quantum mechanics. It is a visual treat, and versatile tool that aids in the development of understanding and intuition about QM. The user can select quantum numbers, and see beautifully executed manipulatable animations of the probability density. Many other features are available. No teacher or student of intro QM should get through the hydrogen atom without spending some time with this.

I have been using b57 since it came out, on Snow Leopard, on my MacPro tower, and it has performed flawlessly. It is perhaps my single most valued tool (although 1Password is close). I have never had a problem or any sort with QS. It is fast, unobtrusive, and effective. I have never had a crash, or a failure to function.