HI;
I believe that "flea market" is something world-wide., comme le marché aux puces, n'est pas?
Maybe the HP11C does not fit your needs, but some few advantages must be emphasized.
[] all available resources are printed in the keyboard; you do not need to search for a particular command spelling in any catalog. You look at the keyboard and see what you need (except for a few shortcuts I'll post below)
[] you have gamma function (x!) in the HP11C instead of factorial (FACT, or n!) in the HP41; you do not need to program these;
[] all hyperbolic and their inverse are ready to use in the HP11C; they are not available in the HP41 as standard catalog 1 functions (you need to program)
[] probability -Py,x- and combination -Cy,x- in the HP11C (same as above)
[] longer battery life
[] (subject note:) the HP11C is easier to learn to use, mostly because it has less resources, although the 41's equivalents are as powerful as the ones in the HP11C)
[] they are one of the most reliable series of calculators HP has ever offered to the users (except for some well known vintage bulldozers)
Some disadvantages are: (against the HP41, not absolute disadvantages)
[] program listings are keycode based, the same way you'd find in some vintage calculators (HP25, TI57/58/59, HP67/97, and many others); it is not a bad thing, it's only time consuming and a bit awkward for users not used to this sort of coding
[] no I/O facilities
[] no ALPHA resources in the HP11C's display, except for a few error messages
[] the HP11C has only 210 bytes of memory available, about half the HP41C's standard memory (1/8 the CV)
I have all Voyager models BUT the HP10C, also the three different HP41 (C, CV, CX), and there are moments I prefer one of the Voyagers (brief calculus, brief SW development, advanced HP15C and 16C ready-to-use functions) instead of one of the HP41. Just a matter of what to do with.
Wouldn't you like to try the 11C a bit more?
Would someone else add other advantages/disadvantages?
Cheers. (I'd never feel offended when someone express his own preferences... Mostly when it's done rationally, as you have surely done)