The HP-9G is the smallest graphing calculator in my collection, roughly the size of a standard non-graphing scientific calculator. The keys have a solid feel and you can adjust the screen. HP also sends two extra batteries with the calcualtor.

Here are some pros/cons:
PROS:
* Very lightweight, for the days you don't feel like lugging around larger calculators
* Distribution functions (normal curve), fractions, base calculators
* Gradient mode (for those of who like to measure angles in gradients)
* Programming available (only 400 bytes though)
* Conversions and constants
* Stat regressions include quadratic regressions

CONS:
* Hard to get two equations graphed at the same time; only trace function available
* Doesn't readibly handle complex numbers (so you'll have to compensate when solving quadratic equations -- the instructions have an excellent example)
* No derivative and no integral function (this why this calculator only got four stars, I consider these two functions vital)

Texas Instruments equivalent: TI-36X with function graphing and programming capability. Worth it if you can get this discounted (thank you Amazon! :))

I bought this because my HP-48 is too big to lug around all the time. Keypad has nice tactile feel. Snap-on rigid case and slide-out plasticized 'quick-reference' guide are good (NB I haven't dropped it yet, but it looks fairly durable...).

I agree with other reviewers that the display of graphs is poor and the display clarity is bettered by other brands/models. In my opinion, the graphical display mode is only useful for viewing a quick sketch of a function. Text/number display is adequate. If the graphing of functions is important to you it may be better to look elsewhere and accept a compromise in other areas.

Most other brands in the price range claim 'algebraic entry - enter problems just as you write them on paper'. In my experience this is never the case - they all seem have exceptions and rules to be remembered and even simple operator precedence (i.e. 2+3x5^2=77, not 227 or 125) is not always got right. HP9g is very consistent and correct in this area. Implicit multiplication (i.e. key 2cos(30)instead of 2XCos(30) or 2A for 2XA) eases problem entry and makes a displayed formula more readable. No built-in complex number handling is a minus point for me. Reviews elsewhere show the HP9g maintains accuracy at extreme values of function arguments - reassuring for professional use. As a working engineer these points are far more important to me than having the best possible display.

Large memory for previous calculations - you can scroll back 25+ lines to check or edit and re-do a calculation.

Quick easy programming in a version of the BASIC language is also a plus point. IF,THEN,ELSE, GOSUB and FOR...NEXT are all supported. Also INPUT and PRINT ease data input and results display which is a major bugbear of most calculator programming.

As you've guessed I like this little calculator. It's no match for the HP professional models (at 6-10x the price...); the graphics might have been better left out; others have better displays: but as a everyday professional tool I find I can use it quickly and intuitively and trust the result where other brands in the same price range have left me wondering if I have really got the answer I wanted.

This is an HP calculator without Reverse Polish Notation entry. This is very similar to TI calculators with an algebraic-type notation input. Those of us who have used the very intuitive (in my opinion) RPN over the years, I am astounded that this is an HP calculator that fails to mention that it is not RPN; not on the box, not on the Amazon description, nowhere. I would return this calculator other than the anti-theft package is destroyed after opening (so it is not returnable), to only find it is a TI-like algebraic input.

If you expect RPN (which I did in any HP calculator) DO NOT BUY THIS!

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