Currently I use a Pi2 but I want to use this one as an OpenElec device and so I would order an extra Pi 1 B+ for my OSPi because it is cheaper.
My question now is if a Pi 1 B+ will be sufficient for the current and future releases of OSPi?
I have mine on an A+ and it works great. Setup is a little trickier with only one USB but it should run cooler with the lower specs and more airflow. I ran a top command today and the Opensprinkler process is only using 2% of CPU and RAM. B+ should work great.