First, we recommend actually measuring BigChainDB's performance for processing transactions, rather than accepting that number they're publishing, which measures the speed of RethinkDB (the underlying database) storing null transactions, and is completely meaningless. We've heard real numbers in the range of 20-150 transactions per second for BigChainDB, but let us know what you find.
As for MultiChain, we've benchmarked the latest alpha at around 500 transactions/second on mid-range hardware and we're hoping to improve that further for the final 1.0 release. But if you're looking for more than 1000 transactions/second, MultiChain will not be a suitable solution for you during 2017.
