Let's start with the simplest financial calculator from HP. There has been a 10b calculator from a long ago, but the current model is much, much better than the previous versions.
From the innards: this calculator is using the same processor as other fast units like the new 12c. A completely new job by the techs in the HP calculator department.
Also, it has much more functions than the previous versions: a lot of mathematical functions (including trigonometrics and hyperbolics, in a financial calculator) and many financial, including break even analysis.
The body and keyboard is much better than the competition - the keyboard in particular ranks there with the best, and clearly better than the HP50g or HP30b.
At the price (slightly below 30 EUR) is a steal, and a much better buy than any of the 12C or 17BII units.
The only thing that puts it down for me is the lack of RPN entry method, and the lack of programmability. If you don't need any of these, then it may be your unit!