HP-15c: Why so popular?

[Eddie W. Shore]

Reasons why I like the 15C:

1. Compact, horizontal format like the 12C.
2. The screen is readable.
3. Solve and integrate functions.
4. All the comparison tests are available.
5. Five labeled keys (A-E).
6. Key codes: easy to locate the key.


The TI-66 is too slow to be a competitor, even though it shows the keys that has been programmed.