Have been reading with interest, as I am Cornish born and bred, and have happily never left! (Apart from my university years) I love Cornwall for the many reasons already stated, and would never move because my entire family and friend network is here. However, it's not all delightful all the time. I do come from a poorer background, and am very aware of how destitute the less pretty areas of the county are. I also work with young people who are from the Camborne and Redruth area and who live in a terrible state of poverty. I took DH to London on our honeymoon three weeks ago (he's never been), and he's definitely even more Cornish than me!
I grew up in Falmouth, and agree that it's probably the best and most up-and-coming place in Cornwall right now. My entire extended family live there, most on the same street. Unfortunately, as a young couple, even though we both have "good" salaries for the county in professional fields, we have been priced out of our hometown. Which I know is the case for many young people across the whole country, but does go some way to explain hostile attitudes to emmets from some people.
From my experience, as a young couple from a poorer family, and having a circle of friends who are also all from the lower economic areas of the county, we generally take a stance of being angry at the presence of outsiders moving in. This is a general perspective, and nothing to do with individual people, but we are angry because we have all been priced out of our hometowns by people from "upcountry". In our eyes, these people are categorised as either second homeowners (dicks who don't even actually live here, so why even bother to drive our house prices up?) or rich London folk with mummy and daddy's inheritance to spend. Ironically, we are planning to eventually buy in one of the "undesirable" places PeaFace was listing within the next five years! They're the places affordable to the minority of young locals who can afford to buy. I don't expect my children will ever grow up in my lovely hometown down the road from their grandparents like I did. It may not be fair, but, in conversation at the local of an evening, we will be blaming the emmets for the house prices.
But, when it comes to individual friendships, I reckon you'll be all right for friendliness. Most people are generally lovely, very relaxed, folk, who you'll get along fine with, so long as you accept the different pace of life and culture (it's quite unique!) here.
And who the hell wants to live in Truro?! There are no good restaurants for a start!