I'm still on my SE. Two years in and loving it. I am running the most current iOS.
As my user name suggests, I was a hard core BlackBerry user. Coming off of my BlackBerry Passport to an iPhone SE was a VERY hard thing to do. The first weeks I wanted to give up and go back to BlackBerry, but after two years, I have found that the iPhone is a much better daily driver.
The iPhone has never failed me nor locked-up. The BlackBerry did have quirks that kept me a bit busy diagnosing problems on a weekly basis. The iPhone SE just works like a trooper day after day. I have realized that "APPS" can be productive as well as fun. I can now do my banking, investments, and other essential daily living things on my phone. That was not possible on BlackBerry. The size of the SE with case is just perfect to pop in my pocket. I opted for a battery case WITH magnet built in so I can mount it to my car magnet holder disc.
All in all, I can't believe how great this little SE has been for me. Sometimes I wish I had a larger screen, but I really don't need it at this point. My next phone will probably be a larger screen iPhone 9 (The SE 2) if that actually comes out.