If you become a huge success on bozzie311.pro you can expect a very large percentage of your hopeful visitors to type in bozzie311.com.
If you are serious about your venture and going to charge out with intentions of winning then my recommendation is to find a great .com. Lots of domains are not being used right now or being underused. Paying $1000 or $10,000 or even more for a great address is worth every penny IMO.
Although there might be 100,000 of these domains registered, most people will say "huh???" when you tell them your web address by phone. Most will forget and type in .com.
I have not gotten to the ranking question and this is a 'no go' for me. However, I think that a .pro will be just as easy or difficult to rank as any other type of domain.
The upside might be fewer robots trying to scrape your content and spam your blog.