I use TTS when I go from reading to driving so I don't have to put my book down.
Anyway, the K2 is pretty good, but I have seen it make some interesting pronunciation choices.
It likes to find abbreviations where none exist. In one of my novels, the writer ended many sentences with the word 'alas' so that the text looked like this: "alas." . Every time the Kindle read this it said "Alaska". I can't recall the other examples, but in general it sometimes has problems with the last word in a sentence.
It can also make the wrong choice on words like "read" (red, or reed?) . I have heard a few other stumbles, but it does an acceptable job.
I'd much rather read than listen and I'm not an audiobook fan. However, TTS gives me the ability to switch modes when reading doesn't work, and to switch back when it does.