Google Shopping is the fastest growing feed based channel in the last 2 years.
There are many challenges associated with doing Google Shopping Feed Management, namely the category taxonomy, constantly changing feed specifications.
Creating an automated Google Shopping feed that performs well takes lots of feed optimization and work, but the payoff is huge. Dealing with ongoing disapprovals is also crucial as they can hurt performance when products are disapproved, or worse yet, your entire Google Shopping account is disapproved.