Well, this is only my opinion, BUT:
I feel all are great number crunching machines in their own right. However, I like the 42s best for its portability. That said, I like the 48G series best for their I/O and simple programmability (keystroke for me) and loads of built in features (lots of functions and conversions so my programming is still minimal).
But I feel that same type of argument applies to the older line 71b vs 41c as well (except that the 41c is indeed more versatile than a 42s simply because it did/does have I/O).
The 71b is a nice machine to use and WAS portable for its day. By today’s standards, you would be much better served by an Hp100 or 200lx (unless you have equipment based upon the modules and interface bus of the older 71/41 line). However, its simple to implement BASIC and its calculator mode were unequalled by CASIO or Sharp, though the latter did make smaller and more portable machines. I don’t believe it was ever intended to be a stand alone calculator due to its high price and I/O capabilities.
Cost and availability have narrowed down my calculator of choice to the 48G series. I use a 48G for all my work, because it has a quality keyboard, has all the features and functions I use (or I can easily download or write). And it is Cheap to replace should I need a replacement (so far, though I have spares). And this is/was important when I worked in the field.
That is no longer the case with any of the other calculators. I do not have a back up for my 71 (actually, I only collected this calculator, never really used it aside from simple comparisons).
My 41c was a gift, and I do not have many accessories.
My 42s was used heavily in school (upgraded from my 15c, also heavily used) and is still my preferred choice (and I have a single backup).
For general RPN use, an Hp32s is great, but since it lacks real RAM, it can only perform simple customabilty (though it would probably be enough for me, I don’t like being cramped). It is really no big step up from a 10c series in capability. I like my 15c much better than a 32s.
And while it is true that my higher end math can be done with my PC, unless I am documenting my calculations into a report, I feel better with my portable calculator. When I used to work in the field, a PC would be a nuisance vs a pocket calculator was an aid and a tool.
All things considered though, these calculators are being used by choice and not of necessity 95% of the time. Most calculator users could indeed do their work with a Ti or Casio with little penalty of functions. However, getting this bunch to accept this fact would be tough (90 % of us feel we are the upper elite and could not work with anything less than HP and that is probably not true for most of us). We are Calculator connoisseurs and do not want to settle for Mickey-Mouse calculators and just want the best available. Most of us could easily get by with another brand, if we were to abandon Hp and our knowledge base and learn a new calculator. Do we want to? No, most of us do not. If fact, the more I learn about the opposition (Ti, Casio, Sharp), the more I want to stay with my Hp’s. But that doesn’t mean those calculators cannot do what I need them to do.
However, those calcs cannot do what an Hp can be made to do. If I tackle simple research and do preliminary calculations for the sake of analysis, (or taking an EIT EXAM) there is no substitute for calculational Horse power (although plenty have passed the EIT’s with calculators other than Hp also).
Most people are happy or satisfied with a cheaper calculator since it is now a commodity. The one percent who feel otherwise do not constitute a market to pursue. And that is why our Hp calculators are no longer available. That is the sad reality the we must face. I hope Hp will release a new RPN calculator with good quality, but I will not hold my breath.
Enough of my Rant.