Let's say Trout's production for the next 6 seasons is exactly what he produced from 2013 to 2018. Then let's assume his production for the remainder of the contract is exactly the same as Pujols from 2013 to 2018. His average OPS+ would be 144. Which would put him 9th in all of baseball in 2018. By comparison, this is the first year Manny Machado had an OPS+ over 140.
If the Angels get 6 years of typical Mike Trout and 6 years of average baseball player this is a great deal for them.