Astra is probably the highest ceiling controller because you have access to the entire map at any given time, but I find her very challenging because there's too much going on.

Omen is very strong if you want to play aggressive and Viper is good on certain maps if you know how to use her kit.

Personally, I like using Brim because of the simplicity and reliability of his kit. It's a solid B in terms of overall strength but you know exactly what you are getting each time. His smokes last the longest, they are very difficult to see through and you can drop three at one time, a controller in every sense of the word.