Still have an Pooleys Aviat 617 in my flightbag. We got it in flightschool (was included in the fee) and i have used it ever since. Nowadays mostly for conversions and to cross check fuel (ltr. vs kg vs lbs vs whatever). All the other stuff is better done by the FMC and in Europe we don't really need to use it for navigational calculation.
But to be on the safe side i even still carry the booklet it came with, nice to explain the stuff i've forgotten about it .)