HP35s Perfect for RPN based technical math.
I went to Texas A&M in 1981 so I learned math with RPN and the HP 10C. It is great to have something as durable and easy to use as that older model. This one just adds icing to the cake by adding programmability.

Excellent -- but not for complex math
It's a fine calculator. I won't go over RPN vs. algebraic and the other features so thoroughly covered in other reviews here. Let me focus on the only "con" that limits it from being a great calculator:

It has lousy handling of complex values.

What do I mean by lousy? I'm not so bothered by the lack of rectangular to polar and back. What I AM bothered by is:

-- No complex square root or square
-- No complex log10 or 10^x
-- No complex hyperbolics
-- etc, etc, etc.

In short, the complex math functions of this calculator are pretty much limited to +-*/ and a smattering of other functions (ln, e^x, y^x). I mean, come on -- a calculator that handles complex numbers but gives you an error for sqrt(-1)?!? We can use the smattering of supported functions to compute some of the missing functions above, but why should we need to??

Most of my use is engineering, where log10 is important. If you never need to compute a dB, this calculator might fit your needs. For me, I'll probably return it.

Much better than the HP-33s
I own this HP-35s and the HP-33s, both I used for the NCEES PLS Surveying exam. The 35 is much better in every way than the 33. The 35 is much easier too look at, all the keys do not run together and it is set up much more systematicaly with menus and such rather than everything scattered all over the keyboard, and it has more memory than the 33. Only thing I didn't like was the manual comes on CD, if you want hardcopy you have to print it yourself.

A very nice instrument
This is an excellent calculator. With the exception that it is not a graphics display calculator, it appears to be able to do just about anything that would be needed. As has been noted in many other reviews, the feel of pressing the keys is superb. It is especially good that entering a program is almost identical to performing calculations, i.e, you don't have to learn one way of doing things for calculating and another way to make a stored program.

Great HP Product
This is a great calculator. The only thing wrong is you have to call HP to get a paper edition of the manual. That is free though, and the manual is on the CD included with the calculator as a pdf. This is a nicer calculator than the ones they are currently selling on HP's website.