if DIY, use something easy like polish angel, applies like traditional wax removes like traditional wax, durability... hmm not sure never got a chance to test it, but it looks and behaves fantastically, with a strong following, so i suspect their stuff is proven and expensive.
the look is not superior to regular sealant in my opinion, since how it "adds shine" is subjective and emotional, look is developed from paint correction. it is advised to spend the money on paint correction before coating because "it is hard to remove after" which i doubt, but if i was going to slap some expensive fluid on my car to make it hydrophobic, i'd like to have the best surface to get maximum shines.
anyway, expect to pay around 300-800 depending on price of coating (brand) and reputation.
consider it a super sealant, that just last longer.
do not expect it to protect your car like a film/clear bra, it wont. Just keeps dust easy to wash off and less "contaminants" stuck to your paint.
i have a bunch of coating material and detailing gear that i've never had the chance to use due to change of my career path taking all my time.