I had this book fairly close to the top of my several hundred years long reading list as I have liked the Twain works I had read to date. So I jumped it to the top.
I have only just finished it as I was late getting going on it and I found it to be a book that I could not maintain much interest in so was easily distracted away from it, including on several occasions falling asleep if late evening :-).
As I got into it I found that I was put into the position of trying to decide whether to Twain the book was predominantly a story or was propaganda. This really struck me first in Chapter 4 where some of it seemed to me to be easily regarded as a rant rather than literature (or not even as a level headed propaganda); some later chapters included similar distractions from the story. This was a pity to me as I felt that the basic story line was very strong but its enjoyment was drowned by redundant and repetitive material if the heart of the book was supposed to be the story, or by propaganda if it was not.
Assuming these distractions were essentially Twain propaganda as to his view of society (and I suspect that they were) then that opens up some questions in my mind about Twain himself. If so then his main social hits were against the related slavery, class, nobility and privilege, and the church. He also pushes some perceptions such as the garrulousness of women; there are lengthy passages about Sandy's garrulousness which seemed to me to go well beyond making what was perhaps intended as just a comic point.
I will leave slavery and the church out of it for a moment and mention nobility and privilege as this is where I really wondered what Twain was up to; were they just a useful part of the story line or propaganda. Twain is known to have enjoyed (even revelled in) the attention he got from his earned nobility status as being world famous. He was also enormously privileged due to his wealth. Also while he seemed to despise class differences, and remembering that during his lifetime the USA was essentially classless and he could have stayed home to enjoy that society, he seemed to spend an inordinate amount of apparently enjoyable time in the "classed" societies of "Britain" and Europe mixing with the privileged, the upper classes and even nobility (and on at least one occasion, royalty).
This contradiction as between his real life behaviour and the propaganda in the book (should it have been intended as propaganda) makes me wonder as to the veracity of his overt hits against slavery and the church, for example. Were his hidden personal beliefs contrary to those he hits against in the book. Did he have internal conflicts over his supposed virtuousness, and if he did so was he aware of those?
Down a similar track I found that he was free with advice on things he had a reputation of being no good at at all. For example, his very lengthy and repetitive passage teaching a theory of wages and prices; Twain was abysmal in his own life as a businessman and investor, at one point losing most everything of his very substantial wealth on foolish business decisions and investments (the main example being in a printing invention of another where one would have assumed from his background in that industry he would not have been so foolish). Interestingly he was assisted out of that financial hole by one of the USA's wealthiest and privileged men. Now he may have just meant his teaching on this as just part of the story and not propaganda, but if that was so it was far too long and repetitive.
For me I found the prose had a slight character that I could not put my finger on as it was not as fluid to me as I would have liked (for my own reading). What I did find was that if I read it aloud in my mind with a slow southern drawl (I can only do that in my mind, not aloud

) it got some life and flowed better. So another contradiction for me as Hank was a New Englander.
When I compare the book to
Huck.. and
Tom.., and also some of his travel/memoir works, all of which I enjoy, I think they have very strong storylines which prevent propaganda, should there be any, becoming burdensome and distracting. I don't think that is the case with
Connecticut...
Note that these are just comments that came from my personal wonderings as I went through the book; I am not making any claims or suggesting anything at all beyond those wonderings that came to me specifically out of the book itself. Personally I think the book would appeal to those who don't look for a crisp storyline and are untroubled by redundant prose (so are like Sandy, perhaps

), or those who like to judge the societal practices of our forebears as individuals against the practices of contemporary society, and that especially so if they feel some guilt when making such unbalanced judgements against the behaviours of their quite distant forebears for whom they actually have no responsibility for at all (see, I can do propaganda too

).
I could go on, but won't except to say

that at the end I was left wondering if Twain had fallen into the trap that some modern artists, especially among actors and authors, seem to fall into in that once they achieve fame and fortune they seem to regard themselves as experts in other fields unrelated to the art of story telling or acting.
If nothing else, I have likely proven that a modern man can be as garrulous as feudal England Sandy was.