I find that I am not favourably impressed by Frank Churchill.
For one thing, his delight at Highbury and everyone in it seems too comrehensive and unalloyed to to be entirely believable. I am willing to believe that he does honestly like a great deal of what he finds, and I will alloww him some overstatement of his positive reactions in the interests of courtesy. But it is all too much, too fulsome, making me wonder "Hmm - What does he really think?"
Interestingly, the only aspect of Highbury which Frank does not find delightful seems to be Jane Fairfax, whom he criticises repeatedly to Emma. In the midst of all his positivity (is that a word?) it's very striking. A lot of his criticism is basically taking up things which Emma has said or implied about Jane, but Frank starts the ball rolling with his comments about her deplorable want of complexion. Does he really think so ill of Jane, or has he picked up from Mrs Weston that Emma is not over-fond of Jane? Is Frank merely saying all this in order to ingratiate himself with Emma?
Frank is clearly setting out to make himself as agreeable as possible to Emma, but I don't much like his way of doing so. He is taking such pains to agree with all Emma's attitudes and ideas. A certain amount of this is to be expected when two people are mutually attracted and in the early stages of a relationship, but I am reminded of Willoughby chatting up Marianne in S&S Ch.10 - (conformity of judgment, taste strikingly alike, he acquiesced in all her decisions, caught all her enthusiasm).
Also, when a man tries to make himself agreeable to a woman by disparaging her 'competition', I will concede that it may be effective by flattering the woman's vanity. But when Frank is willing to be so repeatedly critical and ungallant about Jane Fairfax behind her back, then I suspect he would likely be just as critical of Emma (or anyone else) behind her back if it suited his purposes.
All in all I am not inclined to take everything Frank Churchill says at face value. He strikes me as someone who is not entirely to be trusted.