I consider the Hp27s to be Hp's 2nd best pocket calculator that they ever made.
The best?? Why the Hp42s of course!!!!
I suspect that if the secret of the Hp 27s were to ever get out, it would always bring more than an Hp42s, because the majority of calculator users, USE algebraic. To get the power of a 27s, you need a pocket type pc such as a Casio or Sharp, but neither are offered in a calculator format or pocket form (Casio FX7500G come awfully close).
Ti released a 67 and a 66, but neither were in the same league. Casio's had the 4000 and 6000 series but still that 7K RAM and the 27s portibility and quality make it untouchable in the algebraic world of calculators.
Is it in the same league as a 42s? Not if you need matrix functions as it has none. And it doesn't handle complex numbers, but it has variable names and can use every bit of its 7K RAM, which is more than the new 33s can boast. Actualy has somewhat better statistics with list based data like that offered in the business line.
It also has a built in clock and would make an excellent test taking vehicle (until it formally gets banned).
And it is quite a bit rarer than a 42s because it was discontinued about 3 years earlier, probably do to poor sales. The Hp17B and Hp42s sold much better (and the Hp42s was never, never, pushed or positioned to sell, because every Hp42s sold, meant one less sale of an Hp48G!!!!)