LIKE or CHARINDEX to check String Contains a Substring

Question

To check a string contains a sub string or not we can use [LIKE] or [CHARINDEX]. I know that like uses indexing in case we have name%.(while %name% may not use index) .Also charindex does not use index. For example I want to get all rows containing employeename as 'av'

select * from employee where CHARINDEX('av', employeename)>0

OR i can do same by using LIKE

select * from employee where employeename LIKE '%av%'

In this case which one is better to use? Charindex or like? Why?