I'm on a 2015 iPhone 6s Plus now. I too was planning to upgrade to an iPhone X, until I discovered all the shortcoming it has. Screen size downgrade from my current iPhone, more limited in landscape mode, no Reachability feature, and forced to run iOS 11 with its shortcomings (no 32-bit app support, 3D Touch to enter app switcher, easy backup and sync with iTunes 12.6).
It is basically an early adopter sneak-peak product at this point, with a high price to match, and I think that getting one is a decision I would regret next year.