I'm running these with Rene Herse 650x48 Switchback Hill slicks on an OPEN U.P.P.E.R. and have about 170 miles, half gravel half road. They are great so far. They feel fast even without any aero benefit. They feel light when climbing and my pair weigh 583g for front wheel and 703g for rear wheel (shimano free hub). As expected with 650s, they feel more agile on steering through technical areas, but they're a little twitchy on road descents above 25mph compared to 700c's but easy to get used to. Highly recommend.
I did in-store pickup and it was friction-less. I also called support once for advice and they were very knowledgeable. I'll definitely buy here again.