I have one and it is a pretty good and solid phone. Not quite a smartphone (it runs Linux) and I very much like it. Absolutely indestructible, cheap and unbelievable battery life (so long I sometimes forget I have to charge it at all).
It has dual SIM capability but if you use that you lose the SD slot.
There is also GerdaOS (instead of KaiOS) and you can run Debian on it. When I get my next phone (which could well be years, this one is now 4 years old and still going strong) I plan on running stock linux on it to see what else you can do with it. I paid about 80 euros for it.