Comment Allow for choice (Score 1) 304
I tackle the problem by making it a two step process:
1) Look for some phone hardware that is as open, flexible and as standard possible.
Note that this immediately excludes Apple HW - no openness, no choices there.
2) Select the OS that best satisfies your needs on that hardware.
For (1) I've chosen a Fairphone 2 (5", Qualcomm Snapdragon, 2GB + 32 GB, 2 SIMs + MicroSD, USB-OTG, Headphone Jack, replacable battery), 10/10 on ifixit, built to last.
For (2) you have the choice between Android/OASP 6.1 maintained by the company, regular updates; community supported Ubuntu and Sailfish ports; Lineage 14.1 (aka OASP 7.1) with incremental updates (that's what I'm currently using, but I've test-driven/used them all).
Not cutting hardware & software, but well usable & I expect to get at least another 2-3 years of usage out of this combo.