They're both less than ideal, though the 1100 was tolerable.
Shared faults:
#1 by a long way: Texts not being in monospaced fonts. Sounds trivial, but it means when you are writing one, the word you are writing bounces up and down from the end of one line to the beginning of the one below AND BACK as you change the letter you are trying to enter. Texting would still be very annoying without this, but this is definitively extra frustration on top.
Smallish buttons.
Only a weeks battery life; the 1100 may have been better when new, but no replacement battery ever got beyond a week.
105 (2017) only faults:
It has one big central button, and two either side of that, but they're not buttons. The big one is a tiny d-pad, and for a lot of functions you have to hit the centre, which is non-trivial; usually takes me a couple of tries, can easily get to four or five. The side buttons are rockers, one function on the top, another on the bottom, thankfully nothing on the middle with these, but that's a very minor concession in my view.
Anyone know of anything significantly better?


