The TI 68k devices are great. Or more actually, they were great for their time 20 years ago, and it is a damned shame that no really better device has emerged since. The document centric approach of the Nspire makes them a pain to use and the CAS does not seem to be any better.
That said, you can debate rechargeable batteries vs AAAs (both have pros and cons), but a backlit screen is a really good thing.
> Documents (or being able to have/save separate "calculation sheets") are actually progress vs not having them.
Yes, documents are good. But the Nspire architecture that wants you to create a document before choosing what to do in it and the weird tab idea is not great. As you say, a TI-89 is quick and efficient in comparison, which is why I still use it despite having got a Nspire. If I need to mess around before I can get something useful, I might as well start Mathematica.
> The impression I get from newer calculators is that some corporate decision maker decided that "cellphones are popular and we must copy them".
That is definitely a problem. They are not getting any more ergonomic.
> If you need to use the calculator in a dark room, there's worse problems with your setup than lack of backlight in the calculator.
My eyesight is not perfect and anything that helps readability is an improvement. Sometimes I have to work in the evenings as well.
Having backlit screen is probably the reason why it needs lithium battery in the first place, as a simple pack of 4 AA batteries wouldn't last as long.
Lithium battery has a life cycle of around 1000-2000 charges, and may deteriorate even faster when exposed to high temperatures. Depending on the capacity though, you can expect a cycle to last more for a calculator compared to, for example, a smartphone, so it might not be that much of a problem (but then again you have the backlight, a major drain). When the battery dies, you can't simply go to a nearby store to get a replacement. You usually have to send the device back to the manufacturer to get it replaced.
I can't speak for the NumWorks but battery replacement on the Nspire is trivial and their availability seems to be just fine. Of course the ease of replacement and availability of AA/AAA batteries is better than the lithium battery, but it would not be a reason for me not to get the calculator.
If you want algebra, use a computer. I’m talking about doing calculations and I think it is hard to beat the efficiency when entering them into an HP–48-like device
1. That’s not a calculation. It’s a special case you either need to know or have to be clever to compute. A calculation might be, say, compute zeta(2). But I don’t really want to argue about semantics.
2. This can evaluate this correctly on the (slightly later) HP-49G+
So given this new information, will you change your mind or try to find some other silly example?
"arithmetic also includes more advanced operations, such as [...] exponentiation, logarithmic functions, and even trigonometric functions, in the same vein as logarithms (prosthaphaeresis)."
I own hp50g and TI-89, and I keep picking the latter. It is simply that much more slick.
When using hp50g, I find its input<>reaction latency makes me want to throw it at a wall. I used to tolerate it and rely on the input buffer, but that simply isn't good UX. I'm glad I grabbed a used TI-89 at some point.
Still keeping the hp50g for nostalgia reasons. Is what I used back at university; We went a long way together.
To anyone reading, I'd suggest a used TI-89 or Voyage 200 instead, 68000-based TI calcs.
They cost next to nothing used these days, and there's to my knowledge no better calculators out there.
It is old, but that means it is proven and well-understood.