Call me conservative; up to very recently I used two Nokia 9210i - why?
I
Two reasons, not at all related to each other, but equally important:
- I want a physical keyboard (ok, the Nokia kb is really bad, so this criterion is highly debatable), so the only other current alternatives would have been either other old smartphones (used ones), or that RIM stuff (changed their name but you know what I mean)
- I bought lots of expensive sw for those phones, and most readers will know that, it's smartphone sw developers who very early succeeded in forcing hardware linking (or what is it called?) to users: any mobile phone has got an IMEI number, and almost any (from my experience, 99 p.c. or more) sw for smartphones traditionally has been coupled to the IMEI in question: No (legal) chance even to de-install sw from phone 1 and THEN only install it to another phone: When your phone breaks, your expensive sw is dead.
I suppose this is also true for iPhones and Android (in fact I don't know), but the big difference is, there's a plethora of (also quite prof.) sw for both systems, costing between 2 and 15 bucks, when really useful smartphones-of-the-old-days sw came with prices much higher, and even into the 3 figures.
This being said, for sw developers, smartphones of the old days were a dream come true; it's just MS who today insist upon your sw licence being broken, together with your hardware, whilst decent sw-for-pc developers all allow for re-install when you change your hardware.
II
Now for batteries. As you will have guessed, I cannot use my (virtually "unbreakable": good old quality from the ancient times) Nokia phones anymore since I naïvely thought batteries would not become a problem, those "Communicators" having been sold by "millions", in very high numbers at the very least.
Well, I was wrong: Currently, they sell USED "Communicator" batteries for 3 figures, and my own little stock had come to an end, BEFORE I had figured out I should buy some additional supplies (and then, you cannot store "batteries" / cells (rechargebable or not) forever).
Ok, they now sell big batteries (and with quintupled capacity), with various adapters, even for those "Communicators", but buyer beware: Even if you're willing to use a smartphone connected with some crazy cable to some heavy battery in your pocket (well, in the old days a simple mobile phone was about 10 or 12 kg), this is not a solution since all (???) of these (= from their respective advertizing, not one will have the needed additional functionality indeed) will only work if you have got a healthy regular battery in your smartphone, too; in other words, the external battery can spice up your internal one, not replace it. Why do I know or think I now? (Perhaps I'm even mistaken???)
Now for the difference with many (all???) notebooks: I never had the slightest problem to connect my (over the years, multiple) notebooks to the current, and have them work fine, as long as the respective mains/power adapter was working correctly, long after the internal battery working and/or being available.
The same does not seem to be true with smartphones in general (???); at the very least, it's not true for my "Communicators":
It makes no difference if I have got a worn-out battery in the Nokia, or if I leave it out: Just connecting it to the power adapter (which in turn is connected to the mains of course, I'm not that a lunatic) will NOT do anything in order to my being able to start the phone, it remains just dead, and the same is true if I put the phone into its (equally expensive) "desk stand" (which in turn is connected to the power adapter). And since I've got two Nokias, several (worn-out) batteries, several power adapters, several desk stands, and know about permutations, I'm positive that my problems don't come from some broken smartphone.
In other words, my Nokias need a working internal battery in order to be able to take advantage from any external power supply, and from their respective ads, I suppose those external batteries will not make any difference; my question is, is this behavior typical for smartphones, or is it just typical for the dumbness of Nokia staff? (As we all know, Nokia is gone.)
If it's typical for mobile phones and / or smartphones in general, beware of investing too much into (even a well-sold) smartphone: Once you won't get any more batteries for that, all your investments in that phone will have been flushed.
III
So what I do for the time being? Went back to a combi of Nokia 6300 (har, har, batteries available as for now) and my old sub-notebook (with an internal umts card, reverting to "sleep state" in-between, and as long as the third-party cell will be alive) I hadn't really used any more for a long time:
Since those sub-notebooks are total crap: A regularly-sized notebook is difficult enough to type on (with 10 fingers, nor just 2 or 3) when in the office, you do right and use some decent, regular keybord, so it's obviously a very smart idea to buy some lightweight notebook for the road, but which has got a KB OF REGULAR SIZE (if not shape) - and don't forget the oh-so-useful (both for digit entering as for macroing!) dedicated keypad, and trust me about that; any sub-notebook (incl. those immensely pretty Sony sub-sub-notebooks that weren't continued though and now are available, used, for quadruple their price new) will be a constant and real pain-in-the-you-know-where: It's weight, not size that counts*, believe me, I'm judging from enough unpleasant first-hand experience.
IV
I just read, "Nikon kills third-party battery support", i.e. they probably put some additional electronics in their reflex camera preventing third-party battery makers from creating battery compatible cells: Another (for the consumer: very bad) "highly interesting" "development".
Your respective experiences / solutions would be very welcome.
*= this rule does not also apply in inter-human intimacy