Haven't tried the rocket shoe but I heard the rocket series are more of a volleyball line up. Used Gel Task and Blade 3 before, comfy as hell and excellent cushioning as you would expect from Asics. Not super supportive like Lining Hero nor super fast like Victor SH9000Ace but more friendly to your knees.
The Rocket 6 is a good alternative. It's basically a squash / volleyball / indoor court shoe. My son has it as a badminton shoe and has been wearing for 3 days x 2-3 hours weekly. Asics shoes are good alternatives in the USA since sometimes it is hard to find Yonex / Victor / Mizuno shoes readily available depending where one lives. The Asics Up Court is a more affordable shoe but I would recommend the Rocket 6 over it if you don't mind the little extra cash.
I happen to be looking for a shoe soon and I see Asics has the Rocket 7 out now as well. I may go with either a Mizuno, Asics Rocket 6, 7, or Gel Blade 4.
remember dun buy yonex shoe, resson 1 is too expensive for high end series shoe, resson 2 if you buy the cheaper price shoe the material is very very very bad, resson 3 i cannot believe product made in China.