A PR company is likely to have suitable strategies and contacts to launch to a local market. I'm not sure they'd be the best bet if you were launching a typical SAAS product to a general global market. For a local launch, a lot of it is teeing up publicity and knowledge of the contacts and what they want is critical. For something global, so much of the work is content production that you may be better off trying to do it yourself.
I think of PR as having a fundamentally reactive posture, even when they're ahead of the messaging. Marketing, where there are many freelancers and consultants, would be a much better spend towards creating a strategic approach.
