I've accumulated some experience on X premium. Overall I do see an increase in impressions that is similar to what other users experience- approx. 50% more. Overall it's not a silver bullet. Besides that as a verified member I can make longer tweets and have more options to customize things. I also notice that only the first 3 hashtags of my tweets go into the system while the others are discarded. This is to be expected, I guess the higher premium tiers "unlock" further hashtags. On bluesky, all hashtags go into the system as it is a platform that desperately needs more engagement. As a whole my experience on X shows that outside of politics & news the other subjects on X are pretty disappointing especially compared to youtube. I don't expect to get more than a few hundred legit followers if I advertise routinely for a year.