It all really comes down to what you want to protect your paint from!
Protection against scratches and scuffs + against environment, for nearly the life of your car!, can only be had by clear bra or other good quality paint protection films! One can use any paint sealant over these films to protect them and make them hydrophobic and this easier to clean!
Best part is, your original paintings remains intact against scratches, chips etc.
Check this out - REALLY a fan of Paint Protection films now - BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3)
The seam of the film showing is due to improper installation of the film usually!
I've seen some proper installs where the seams are completely hidden between panels and one cant even tell that there's a film there! The above link just made me a huge fan of the paint protection films!!
And in case your film becomes dull, you can easily polish the film too!
Protection from only the environment(including uv) with scratch resistance for upto 1yr or more can be had by ceramic coatings! (these coatings are really hydrophobic so help in cleaning too.)
Protection from only environment with slick hydrophobic paint for 2-3 months max = quality paint sealant
I'm a detailing enthusiast and have used coatings like GTechniq, Cquartz and Opticoat 2 and I love them!
But I still use paint sealants and carnauba waxes as they take my polished paint to a whole new level of shine! They don't offer any protection from scratches though!