What is the "effects error" you speak of?
On the whole, AE CC2015 is working reliably enough for me to get professional work done every day. There are some distinct problems which I work around, and for anything that has seriously broken my normal workflow, I just use AE CC2014.
No doubt CC 2015 will continue to get better with future updates.
Speaking of future updates, there's supposed to be a very significant update to AE this month. It's meant to add some new features, change some UI elements, and fix a whole lotta bugs.