I do. I always do my best to support the games I play, especially when they run a FTP model. The benefits for plus members make it a no brainer, too.
However, I lately have become more and more bored and disillusioned with ESO, and I find I miss the older style MMO's...which means I will probably be spending less time in ESO in favor of Brad McQuaid's new project. At that point we'll see if I still keep plus.
I'm no longer playing so why would i need ESO+