RC isn't bad for Kirby, though you have to be careful who you CP it against. The problem with this stage is that while the whole fight is fought in the air practically, it is never offstage, which is where Kirby shines. What I mean by this is that other than when you're at the pendulum, gimping is pretty much undoable due to the fact there is almost always a platform below you.
Also, Kirby's airspeed isn't too fast, so some characters can get around him easily here.
Still, this is definitely not a bad stage for Kirby. He does have a lot of things going for him. While many characters will just try to survive here, especially those with bad recoveries, Kirby can focus on delivering a volley of aerial attacks and generally ****ing over the opponent. Also, there are a few spots where Uthrow can kill at any percent on this stage. Inhaling and aerial hammers also seem easier to hit with here, and projectile campers are going to hate you here.
Overall, it's a good stage, but I wouldn't pick it against MK, Pit, Jigglypuff (especially Jiggly. DONT CP HER HERE!), Marth (unless you like to eat rising Fairs), or ROB.