Man that's a tough one. Well if you dont own a Soundwave and or Soundblaster already I would go with Hot Rodimus. If you like how he looks from pic's you have seen then you wont be dissapointed. He's a perfect Hod Rod Alt and despite the Kiss Play hate the toys are very excellent. However if you have yet to get or own a Soundwave, Hot Rodimus can wait. Soundwave is going to go very fast and I would grab him up sooner rather then later as your wallett could pay the price later on. Better $40-50 now then 100+ later on.
I'd say Rodimus. There's already Takara reissue of Soundwave that you can get and unless you don't like the whole pedo issue with kissplay I don't see why you'd want to pass up Alt Hot Rod.
Soundwave. Kiss Players makes me wanna throw up on whatever dumbshit thought that stupid line was good.