Wordpress(.org) is decidedly more professional than other blogging platforms. It has many, many benefits and is easily customizable. The plugins available to wordpress users can really enhance the blogging experience for both the blogger and the blog readers. It is hands-down the BEST blogging platform available and it's frequently updated, so you're always on the cutting edge.
If you transfer to wordpress from blogger, I'd highly recommend that you choose wordpress.org which is the self-hosted solution. Sure, it'll cost you money to register the domain and pay for hosting but those costs are relatively inexpensive and the move is totally worth it. Wordpress platform and plug-ins are free. You are in complete control of the blogging experience and it is fantastic.
I transferred my blogs from blogger a while ago and never looked back. It is the BEST decision I made. If you need help making the transfer, let me know.