It's always a compromise. If you want the ultimate in comfort and less potential for detection by touch, an all swiss lace unit is the way to go, but it's not going to last as long as a french lace based unit. The french base/ swiss hairline combo works well because the durability of the french lace is an acceptable tradeoff in most people's opinion.

Whatever you do though, make sure you get the unit reinforced at the point where the sideburn meet the ear, especially if you are getting swiss lace in this area. Unless you get french lace in that area of a double layer of swiss it will literally disintegrate from the stress.