A15 shows promise but is still too anemic for enterprise use cache and address space wise. I have no doubts it will transform into something quite impressive in the future, though.
The future development of the A15 (or follow on) is what I am referring to when compared to any type of future development of the POWER. I just don't see the POWER Licensing issue being taken that seriously because it's so late to the dance. Add in the rumor that significant number of POWER engineers are being shown the door in a month or two which creates a dicey for future development by IBM when ARM has a forward, but slow, development pace.
I've used an A15 machine in the past (Chromebook) and found it to be a hideous experience, and Google went back to Intel CPU's for the Chromebook Pixel. That being said, for the price the ARM Chromebook was well received, but I found the machine to be darned near unusable.
OTOH, the ARMs being used in tablets are getting pretty decent and cheap:
http://hothardware.com/Reviews/Google-Nexus-7-2013-Review-Improving-Upon-the-Best-Android-Tablet/?page=1For $229, I'm tempted in getting one.