Astra SP are great value for money and a good benchmark. GSB are a little better in sharpness and smoothness but cost more but I do get more shaves out of them.
On straight bar de razor I like Astra Green Platinum blades. On slant bar de razors I like Kai stainless steel blades. I do also appreciate Personna blue blades and Feather Blades.
At the fird place there are Gilette Blue blades, Gilette 7 o'clock blades and Sputnik blades.
It depends on how often I shave. For years when I shaved every other day, IP Red and Astra SP were my favorite blades. Since Covid, I'm shaving every 5-10 days and needed a sharper blade. For the past year, I've been using Personna "Swedes".
In order of preference:
Dorco Prime STP301 & STP300 (same blade just plastic vs paper tuck)
Dorco Stainless ST301 & ST300
Astra Superior Platinum
Derby Extra
Dorcos and Astras are similar for me. Just get a few extra shaves out of the Dorcos
Derby Extra also works well though they do not last nearly as long as the other blades.
Note that for the Dorco blades the above refers to the newer product that is made in Vietnam and labeled as having HQ technology.
Some B&B users have reported mixed results from older made in Korea Dorco blades.
Anything made by Personna, Muhle, Feather and German Wilkonson. The Gillette blades are meh and the Bic's are horrid tug jobs. (for me, others certainly would disagree)
i could use nothing but Personna going forward and be 100% happy.