5 SQL DBAs for

~30 production instances from 2008 to 2014 (mainly 2012)

~25 pre-prod

~10 QA

~45 test/sandbox/dev

~1800 DB up to 2TB (total ~70Tb)

Windows clustered instances, Availability Groups, Transactional replication, log shipping, mirroring, SSIS, SSRS, SSAS, SAP, Sharepoint, Biztalk ...

we mainly use custom alerting/monitoring based on SQLAgent, SQL alerts, SQL policies, SSRS ...

we want to buy a tool to centralise/standardize monitoring/alerting/analysing for all our servers but for the moment we dont find the one suits to us 😀