Smart Filters are the last major feature to be developed for MultiChain 2.0 Community, and are scheduled to be available in late summer (hopefully September). Of course, this is software development, so things can be delayed, but so far we are progressing well.
You can find some details of the Smart Filters design in this page:
We hope to publish an in-depth comparison of smart contracts vs smart features together with releasing the feature. But the core difference is that smart filters act to validate individual transaction or stream items, to determine whether or not they can go on the chain. By contrast smart contracts are code embedded in a chain which responds to transactions after they are there. So smart filters are applied earlier in the transaction life cycle.