i've tried all three brands to an extent (i have quite a few byredo samples, 5 bottles of diptyque & a solid perfume, 1 small bottle of le labo), so i hope that i can help you in some way!
- le labo has the strongest lasting power i'd say, i find i can still smell it on me after a long day, and it's a bit of fun going into the store and getting them to mix it all up for you and such, but their price point is really high for what you're getting imo and the majority of their offerings aren't all that interesting to me. thé matcha is the one i went for, and i'd go for thé noir, which is incredibly nice, and maybe santal 33 if i had that kinda money. it's really just a struggle to justify the price point when i can think of a lot more interesting brands that provide a more premium experience and quality at a similar price. i like their shower gel though, the basil one smells fabulous
- byredo for me is another one that is really cool in theory but ultimately falls short in their actual fragrances.. i do like them a lot, but i find quite a few of them smell very similar to me (there are a few that i have trouble remembering which is which cause they have such a similar dna hahah) their price point is more understandable, their bottles are really cool and tactile, the people that work for them are nice and the lasting power is pretty average. doesn't necessarily last all day unless you've got the fancy brown liquid ones. i wouldn't say they last as well as le labo does in my experience, but it's not a screamingly huge difference. highlights from them for me (of what i've sampled) are rose of no man's land, la tulipe and sellier (sellier is really really nice and really really overpriced). try out their makeup and candles too if you're into that! i love their makeup a lot i think it's really fun and nice quality
- i am a ride-or-die diptyque fan so i will try my best to not sound biased but i just find their fragrances all to be really interesting!! i will definitely admit that the lasting power isn't totally there on the eau de toilettes for philosykos (which disappears very quickly which makes me very sad because it's one of my ultimate favourites) and tam dao (i can't speak for any of the eau de parfums because i don't have any yet) but l'eau papier and eau rose last decently long (not as long as le labo though..) and they're both incredibly lovely. the price point of the small bottles of the eau de toilettes has gone up over the past couple of years which has made the lack of lasting power a bit harder to justify, but i suppose it's worth it if you're really into the smell itself, like i am. the solid perfume is also a really great price point - i have orphéon - and it doesn't really project the smell to others but it lasts for a good while especially considering it's a solid, and the fact that it's refillable is super nice and convenient. wouldn't entirely recommend their candles despite them being quite literally a candle company just because a few of the scents smell a bit samey when they're burning.
really from all of this my best advice would be to grab a few samples from each brand and give them a go in your own time and see what works for you! luckyscent is a shout for most countries to get samples from - i hope this helped a bit :)