Packrat parsing vs. LALR parsing

Question

A lot of websites states that packrat parsers can parse input in linear time.
So at the first look they me be faster than LALR parser contructed by the tools yacc or bison.

I wanted to know if the performance of packrat parsers is better/worse than the performance of LALR parser when tested with common input (like programming language source files) and not with any theoretical inputs.

Does anyone can explain the main differences between the two approaches.
Thanks!