Hi Chaithanya,
Pros-
You can have more amount of data processed with better performance.
Monitoring and maintenance will be easy.
Of course read Eng Swe Yeoh blog.
More flexibility to on codes to support Web Services integration
Cons
Less use of standard codes and tables.
The effort will go in re-doing the proxy code once you switch.
Recommendation-
If lot of standard BAPIs are involved keep RFC for them and for custom go for Proxies.
Otherwise go for proxies.
Regards,
Vikas