Transaction processing technologies: comparative review by reliability/performance ratio.
Practical experience: 4000+ concurrent active users, 17 millions of lines of documents processed daily (~40 millions accounting transactions).
Nobody has tested a bigger number, so far.
Based on the example of a real user (an e-commerce retailer with ~$1billion in turnover and ~30,000 orders a day), the speed that the zipchain-ray grew at, measured by the local proto-dia$par, was around 40 million zip-transactions every day.
Writing all of these using the classic accounting method of A4 paper would create a stack 30 stories tall (daily).
Processing a similar number of transactions using Bitcoin's blockchain (a world wide network) would take 6 months.
Independent testing: 18 000 concurrent active users, 96 millions lines of documents processed daily, bigger load is possible.