Need your help guys. Looking for a new laptop for my son who is turning 15 next week.

Budget is £3-350

Looked at these so far

http://www.argos.co.uk/product/6738345

http://www.argos.co.uk/product/6772985

http://www.dell.com/uk/p/inspiron-15...15-3552-laptop

http://www.dell.com/uk/p/inspiron-15...15-5567-laptop

Can anyone recommend any others or which would be best out of the ones above?