If you don't need trig functions, I would also suggest you look at an Hp17Bii (actually the older ones are still easy to find and not all that expensive). It will have a quality keyboard, 7K RAM, a nice solver (You give up programming, but the solver is actually easier to use). And you keep the enter key in the old location. Form factor is better than the newer Hp33s (even the new Hp17Bii+, which has 32K of real usuable RAM, but enter key is moved and all newer keyboards are quality suspect, though may still be acceptable).
If you DO need trig, you could consider an Hp19Bii which is a bi-fold device with similiar specs and behavior to the Hp17Bii. But you could also buy a used Hp28s or 48G. Both are about $50 via ebay (same price as a new Hp33s). Both are better than an Hp33s for power, but both are graphics and bigger in size as well (though the HP28s probably isn't much bigger).
For power, the Hp48GII/Hp49G+ series blows the poor Hp33s out of the water. The Hp33s specs measure up close to the Hp41c for features. The Hp33s is basically an Hp32sii with extra RAM and a redesigned keyboard. You can find some comparisions with that in mind. The Hp41c is of course a much more versatile instrument than an Hp33s, but for number crunching, you might be very well served with the Hp33s. Similiar programming in RPN, plus you would also get an algebraic solver. You would be hampered by a 26 variable limit with no way around for program usuage ie, while you do gete 32K ram, you get no way to use more than 3-4 K in reality. All I/O is done through your fingers and the LCD.
But it is the best available retail for an RPN scientific (basically the only thing available).
The Graphics calculators are actually RPL and have no 4 line limit of the RPN programmables.
You would probably like the older Hp17Bii best if you don't need trig, if you do need trig, you are best off with the Hp33s. If you want a powerful new calculator, the Hp48/49 series is great, but lots of new things to learn.