My brother can't read any longer, well, long enough to read a novel, so the TTS has been great. He uses it both on the Echo Dot (which I made him buy) and on his cheapo $49 Fire. It does take a little getting used to, but after awhile, you think nothing of it. But I DO recommend trying different voices - I like to switch between British and American voices depending on the novel.
Yes, I have now abandoned KK's TTS unless I'm at an appointment and just can't read any more. Then in goes the headphones and on goes the TTS. I'll use the KK as my take-a-long until it dies.