I've just tested Fruityloops as a VST and Acid 4 and it's all just crap!!(I might be wrong)

Acid 4
Prob 1: Acid 4 doesn't automate all plugins (only the soundfoundry ones)
Prob 2: Acid 4 doesn't have a CC Controler automation (for automating hardware synths and samplers)

Fruity VST
Prob 1: I can only use it as a "sample player" not as sequencer(like in piano roll) = so kontakt is a better choice for that
Prob 2: The automation in fruity VST doesn't work while the host runs
Prob 3: Fruity VST doesn't sound at all if the host is stopped

PS: I love Acid's audio sequencer and I love Fruity (standalone) but they need to get much better with the new feactures!!(I know they will).

And please, correct me if I said any bullshit

Peace
--PSY 4 EVER--

No, you're right... SoFo screwed up with Acid 4, and they're in the process of fixing all the bugs... (for example, the serious problems with fruity that everyone has been complaining about).