I always loved Katyusha's dub voice (Hillary Haag, who also did Yasuna in Kill Me Baby, Becky in Pani Poni Dash, and conèche Satsuki in Ghost Stories). It bothered me at first how dub Katyusha would always say "Katoosha" instead of "Katyusha", but that pronunciation kinda grew on me because that type of almost childish mispronunciation of her own name does seem fitting of her character.
I never actually watched GuP in Japanese so I don't really have a reference for how Katyusha's original voice sounded, aside from maybe some clips on YouTube or whatever... But yeah, despite some people's complaints about the GuP dub, I do think that they did 'Tyusha good. Hillary Haag managed to pretty perfectly convey Katyusha's whole energy.