Journals that do not demand for processing charges seem to lay more emphasis on peer review and take a lot of time during the process while those with publication charge are faster. Which of these categories is better in term of standard? Why?
I will agree with Dr. Mahesh Kumar. It depends on the author, if you can cope with the long period before some already established journals like Elsevier and the likes that may not demand article processing charge, you may publish with them but if you want your paper to be published faster in few weeks or months, you may go with such journals. I believe journals that didn't request APC are very credible with quality and thorough peer review process than those that charge heavy for publishing charges.
It is considered that the journals without any publication fee are more competent, skilled and reliable. This question is very important and we must discuss this topic. I think it depends on the editorial board of the journal and impact factor as well.