I am a oneplus fan. I'll put that out there first. I do, however keep a year to 18 months behind. I'll get a cheaper 6T when the 7 or 7T comes out. I got a cheaper 5T not so long ago.
Reasons for sticking with OP for the foreseeable future:
1. Monthly firmware updates. I don't see anything bar google being as good.
2. Value. Still not cheap but great value.
3. Near stock experience.
4. Headphone socket - though just moved to bose wireless so not so much a problem.
5. It's not Huawei / Honor - I will never buy anything from them again.
Things I dislike:
1. Monthly firmware updates. very occasionally they mess up - it's fixed quickly but has happened.
2. Far away support.
3. Not being able to walk into a shop and get one.
Just my thoughts.