I have both the HP15C and two HP16Cs, though I am not old enough to have bought one new. :o) Truly awesome calculators, even if they are a bit slow sometimes. The form factor of the Voyagers is amazingly perfect; in fact the ratio of the length to width is approximately the Golden Ratio if I recall.

I use mine regularly as I prefer a tactile instrument. Plus the mental challenge of implementing programs in a constrained environment is invigorating.