People hype it because:
1. Blast has the best casters. Scrawny and Launders are the best for me and a lot of other people. And Anders and Semmler are good as well (I'm not a fan of Semmler though).
2. Analyst desk. I cannot emphasize how important it is to have a good analyst desk in CS. You have ten players on the server meaning a lot of different stuff happens on a match. Having a good desk that has both the CS knowledge and the ability to properly convey it is very important. Pre and post-match interviews are particularly important (particularly the latter). Asking the right questions or rather asking what the audience wants to know is key even if sometimes they must be tough questions. Blast excels at all this while ESL is meh at best. Maniac is by far the best analyst CSGO has. Pimp is great as well.
3. Content. It seems looked a bit into Blast and tried but IMO failed. I personally have no interest in watching surf maps. Blast has completely nailed this aspect. They put players through every type of mechanical challenge, they have trivias, skin-related stuff, etc. With ESL, I just mute the stream until a match starts.
I feel like Blast has much better observers. During Katowice, I felt like I missed a lot of highlights because the observer missed them.
The best thing ESL has at the moment is the Machine+SPUNJ casting duo. I still prefer Scrawny and Launders but they are great.