I doubt we can ever truly know if there are significant differences in speed, rolling resistance, etc. on tires that weigh about the same. That's because scientifically conducted tests come up with different results. That's because of differences in tire inflation (how many of us pump up our tires up to the exact same pressure each ride?). And that's because advertised tire weights vary, not to mention that most people probably don't consistently use the same tubes with the same tires, tubes which have their own characteristics, like weight and suppleness.

Above 200 grams, I've had good luck with just about any tire I've tried over the years. That is, I can keep up with other rides and I don't get many flats. Whenever I've tried super lightweight tires, though, say those advertised at around 185 grams, I've usually been disappointed, not in the ride, but in how fast I destroy those tires on the mean streets of Los Angeles. Usually, sidewalls get cut too quickly.

Super lightweight race tires - and tubes - always make me think my bikes feel noticeably lighter, and I feel like I'm going faster uphill. I have a feeling, though, it's based on confirmation bias. I spent a lot of money, so my purchase must be doing what I want it to.

I mostly choose tires based on advertised weights of 215 grams or less (I've been surprised to discover than 215 gram tires usually weigh a little over 200 grams), followed by how good the tires look like on my bikes.