Originally Posted by
CliftonGK1
Featherweight clippy fenders have their place: Bikes that can't clear full fenders, or don't get used in bad conditions very often so you want the option to easily remove the fenders.
They're great for keeping spray off your bottles and backside... but that's about it.
Full fenders can be a PITA to mount properly, especially Honjo/VO/Berthoud fenders which require drilling, etc. The benefit, IMO, is when you add a long mudflap to full fenders. A long & wide front flap keeps from getting spray on your feet as well as mucking things up on your drivetrain. A long flap in back is a courtesy to anyone your ride with, as you won't be spraying them with road grime. The drawback is difficulty to remove them, so most people just leave them on, even in the summer. (I joke with riders who comment about my fenders during sunny summer rides, saying they're to protect my tires from UV damage.)
I put a big mudflap on my front clippy. It keeps the junk off myself and the drive train nearly as well as a full fender with mudflap would (I have that set up on a different bike).
The downside with clip-ons is that they don't protect your brakes or the underside of your fork. The front derailleur gets some grit thrown on it by the rear tire as well.