I had CK over three years ago (39 months ago). I had a pretty severe reaction to the treatment but an incredibly positive outcome:
Immediately after getting CK, my balance got (subjectively) about 15% worse (for around six months) and I suffered very profound fatigue (so bad that I could barely lift my head off the table and sit up straight and I was short of breath, for about a month). Strangely, my tinnitus immediately reduced in volume about 90% after treatment and has never returned since to its former loud volume. My doctor (the preeminent Dr. Chang at Stanford) told me that the tumor was reacting strongly to the treatment, which was a good thing, and I just needed to ride out my fatigue and dizziness (or take steroids, which I declined). He assured me I'd feel better soon.
Boy, was he ever so right. After swelling 33% in volume (at the 5-month mark post-CK), my AN shrank an almost-unheard-of 59% over the following six months (as shown on my 11-month MRI). It is now smaller than when it was first diagnosed. My balance began improving six months after treatment, and my energy came roaring back. I'd say my balance now feels like it's about 80% better than it was at the time of treatment.
I did lose a little hearing (around 15 dB) in my midrange and high frequencies, but I also gained a little bit back in my bass frequencies. Had I gone with surgery, I would've left the operating room completely deaf on my AN side (because of the size and location of my tumor; YMMV). Instead, because I opted to receive CK, I still have very useful hearing on my AN side.
If you want Dr. Chang's opinion (which he gives at no charge), email him at sdchang@stanford.edu. I cannot speak highly enough of him. He, and CK, gave me my life back.
Best wishes,
TW