The One still a GREAT phone almost two years later; ( my opinion )
I'll make this short, I got the OPO back in late Summer 2014, after replacing my damaged HTC One M8 ( which I LOVED, and converted to GPE ) The Kit Kat ROM's were awesome on the OPO, giving me like crazy 7h Screen On time, I liked the shape and design of the phone, it sort of seemed like a Nexus 5-1/2, the Nexus phone Google would have made after the Nexus 5, if they didn't go Motorola. The OPO has a sort of Galaxy Nexus + Nexus 5 combo design going on, in a good way.
Yeah I hate OPO's invite system, and all the BS within the company, and to be honest the OnePlus Two does ZERO for me, I have no interest in that phone whatsoever. Seems like a side grade at best to the OPO. Plus not a fan of the SD810, so put me down as a OnePlus Two hater
Since I bought the OPO I have had the iPhone 6 Plus ( Jailbreaked, just to try out a big iPhone and the JB scene, but iOS blows IMO, ran back to Android less than a month later ) Then I bought the Nexus 6 which I liked a lot, especially stock Android and AOSP ROM's, but the Nexus 6 was really crossing that border for me size wise, just too wide. And now I currently have the Note 5, running a good custom ROM. The Note 5 surprised me, as I typically don't like Touchwiz, but with a good ROM, it really is fast and smooth, and of course the screen and camera are #1.
My point here is, I still kept my OnePlus One as a back up phone, but for a long while was left in a drawer for months, so I dusted it off, and installed Sultan's CM13 ROM, and holy ****, I forgot how much I liked this phone, and the stockish vanilla Android type OS of CM13 vs. Touchwiz is so nice. I am SIM swapping between my OPO and Note 5 every few days, I really like the OPO still, even compared to my Note 5. Yes of course the Note 5 is a better phone no doubt. But here's something special about this OPO, like the old EVO 4G thanks to XDA that lived on a very long time, this OPO is one of those few special phones, with the help of the great development community will live a long life. Plus the hardware is still pretty fast in the OPO, it's not like a slow turtle or something.
I hated the OnePlus Two, but the One X really surprised, looks like a great phone. I am very optimistic on the OnePlus Three now, if they can design it sort of after the One X, similar build quality and design, but with the SD820 + 4GB RAM, with a 5.5" screen, and keep the price around the $400 range or so, it could be another killer phone.