Latex tubes, paired with high quality tires, provide great road feel and modestly lower rolling resistance than butyl tubes. Silca's are designed for wider tires (think 25mm ), and work nicely with wider contemporary clincher rims, which can add 2-3mm effective width to your tires. The valve stem-42mm-is perfect for most low profile rims, and not uneccessarily long given that deeper rims will need extenders anyway...These tubes aren't cheap, but last long and are worth the extra bucks to optimize your ride.
The Latex tubes were less fussy to install than I feared they would be. now with several hundred miles on them they feel inspired. The ride is more comfortable than t was with the butyl tubes, I adjust the air pressure before each ride....a very good purchase.