I deeply and genuinely hate them. It is one of those fairly uncounterable sources of tremendous damage. You can't systematically avoid them because of their high range and one bolt always takes over half my hp with any build or gear, which really shits on your round. This has nothing to do with my opinion on their balance, it's just purely the concept of medieval snipers that is no fun for me as a melee player. I hate them more than archers. Getting shot by an arbalest from a 100 meters distance, losing most your HP, it just feels more shitty than almost anything. Just bad luck, or worse, people having figured out you are a priority target.
Balance wise, the amount of melee efficiency they have to sacrifice for their ranged efficiency is really low. Their range efficiency is clearly very high, and because they always hang back and retreat they often fight in 1 vs 1 or 1 vs 2 situations where the 8 athlethics with a blunt/pierce weapon are godlike builds. I got a bunch of clanmates who are top notch melee players who played crossbow a lot for a while, and the package of easy ranged and easy melee kills made them go 20-2 continously.