My 1199 had a valve cover leak (seepage), which I fixed on my own and was pretty simple once the subframe was removed, and that's pretty easy. It was the vertical cylinder so I can't comment on the horizontal replacement. I had 14K miles on the 1199 and that was the only gripe.
Fast-forward to trading that 1199 in for a 2015 1299S with only 1,080 miles on it back in 2017. Immediately purchased the Ever Red warranty which took me through 2020. Went through the entire warranty period without needing it, but for $600 it was well spent for peace of mind. I passed 10K miles recently and about a month ago the thermostat housing went (known as the squirter assembly). It was a pain in the ass replacing it, mostly because the stupid clip type clamps found in the parts manual leaked from the get-go (ordered new ones for the job). Through some screw type clamps on and it's running great again. Aside from that thermostat issue I've only replaced the chains/sprockets, brake pads and a battery. And as others have said, bleeding the brakes/clutch is a common requirement which I do a few different times throughout my riding season.