I'd wait. Last year, before the 6 was out, I had been using a "dumb phone" with a slide out keyboard for years. Not out of choice, but because I couldn't afford the latest and greatest (high school student at the time). Then, I got my first job and had enough money in July 2014 to buy a 5s outright, but I decided to wait the extra 2-2.5 months for the 6 to come out. I'm really glad I did, and I think if you wait, you'll feel the same way. If you can live with your OPO for just 2 more months, I'd suggest waiting for the 6s.
