In terms of cost comparisons, I don't have any raw data that I can share - so, apologies and feel free to take the number I stated with a pinch of salt. In ter

In terms of cost comparisons, I don't have any raw data that I can share - so, apologies and feel free to take the number I stated with a pinch of salt. In terms of security, z-series can be configured to meet the common criteria EAL 5 and beyond. Which is pretty d*mn secure and I don't believe can be matched by commodity hardware. In terms of transactions per second, which is one of the most important metrics here, the z-series can cope with up to 1.1 millions per second. I believe the chunkiest single AWS instance maxes out at 10,000 tps. Then there's reliability... a lot of these mainframe beasts have years, if not decades of up-time in a lot of cases. On the downside, developing on them is clunky and there's a severe shortage of expertise. College graduates barely even know mainframes exist.