More and more people seem to be opting for dry verge and ridge systems these days.
s i've mentioned on other sections on this site, (apart from the general clean look of upvc's and dry systems) it is primarily down to the maintenance side of these products, or lack of as the case is.
All properties that are built with a gable end will originally have had the gap beneath the tiles pointed with sand and cement, which over time starts to perish, cracks start to appear and eventually if given enough time, will turn to dust. The same is also true of the sand and cement your ridge were originally bedded and pointed with. It too will urn to dust.
With dry verge and ridge systems you no longer need to worry about a roof littered with debris, falling mortar or the need to re-point and maintain these parts of your home.
Both systems can be installed quite easily and both systems are compatable to almost all makes and profiles of single lap tile.