It depends on whether you come to it as an established British-style cornet player, or a trumpet player, in my humble opinion. As a British cornet player, you are used to playing with a sweet, mellow tone, so the flugel is a much easier instrument to get into because you already play that way. If you are a trumpet player, you'll generally have a much brighter tone and be used to playing more - how can I put this? - 'heavy-handedly' so you have to get used to toning that down to a flugel. I've heard trumpet players murder the cornet, so it's easy to see why they are intimidated by a lil' old flugel.