After many years as a professional detailer, (no longer in the business now) working on all makes and models from the humble mini upto car collections of Lambos, Ferrari's and Veyrons plus many many ultra specials. Being Swissvax approved as well as associations with other companies, the main thing I learnt and told clients was that light coloured cars look better with a sealant finish, whereas darker respond better to a wax finish.
As for what product, that's very subjective, down to individuals eyes, budget and needs. Collinite make great products and I never left home without them in my van, the same as true with Dodo Juice, Klasse and of course Swissvax (all the way up to Divine). Collinite 476 is amazing on wheels and the body, but does leave a plasticy sealant look so again better on lighter colour motors in my mind.
You also need to consider how often you want to be treating the car, a good quality wax or sealant can and will last 12 months, but only if the washing process is done correctly. The best car shampoo I ever used and swore by was and still is Johnson's 'no tears' baby shampoo, it cleans all dirt off but does not remove wax, try it its great and it will allow your chosen finish to last far longer than almost all other car shampoo's