Comparing the 33s data sheet with the prematurely released (and maybe not even right) 35s data sheet shows that these calculators are very close siblings:
1. The processor (SPLB31A), memory (31k), and batteries (2 x CR2032) are the same. The display is the basically the same (2 lines x 14 char) but it may have some annunciator differences.
2. The 33s has 48 keys while the 35s has 43.
3. The firmware is obviously different because the 35s has 800+ registers vs 27, imaginary numbers are handled differently, and the 35s has 42 constants while the 33s has 40.
The 35s data sheet also says it is the only scientific calculator available that can do algebraic and RPN entry. This implies the 33s will be taken off the market.
My only gripe with the 33s has been the keyboard form and cluttered layout, so I am very happy to see a revised version that actually looks and hopefully feels like a traditional HP calculator. I'll probably buy three. One for the office, one for home, and one that will remain unopened until one of the other two fails after 2027. If I only bought three HP-11c's in 1987 for the same purpose ...