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This calculator directly competes with its TI contemporaries, the TI-89 and TI-92 families. For a nice comparison see this page on area48.com (link valid 2022-12-30).
If you, like me, have ever used overkill tools like muMath (link valid 2022-12-30) or Mathematica (link valid 2022-12-30) you'll appreciate the simplicity and ease of use of the symbolic math functions of this calculator. With "simplicity" I don't mean that it is not powerful, on the contrary, it is versatile and configurable and performs dynamic derivation, integration and linear algebra with ease.
And that's not all. The screen is big and configurable. It has a very powerful editor for formulae entry, but diehards can of course use RPN for everything, including formulae entry. I prefer the RPN method myself but catch myself accidentally using the editor how and then. :-)
Also nice is the option to switch the calculator to "exact" mode. In this mode the calculator will only produce exact answers. This can result in very long answers when using the "x!" function. It also produces exact answers to some trigonometric formulae, like sin(π/4) = √2/2.
This calculator is machine-code programmable and various utilities and games can be downloaded on the Internet.
Not to forget, the many so called "Easter Eggs" in this machine. Visit this page eeggs.com (link valid 2022-12-30) for some examples.
Some drawbacks. Everything has drawbacks. In my opinion its power consumption is quite high. Fortunately they're plain and cheap AAA batteries. And I don't like the huge amount of pressure needed on its keyboard. After using this calculator for a while my fingers start hurting.
There's also some information on the HP 49G on HP's official website (link valid 2022-12-30).
For more information on this beauty please refer to the better sources, like The Museum of HP Calculators (link valid 2022-12-30).