You can be up and running quickly, focusing on the content that is relevant to your business and your clients. The site does not have to present itself primarily in a "blog" format; posts can be eliminated or used for more a more traditional "Press Release" look.
2) Lots of hosting options:
Hosting options for WordPress run the gamut from no frills to fully managed. WordPress's low resource footprint means it can be hosted on smaller accounts as you get started. Your resource requirements may grow over time, but it will be mostly inline with your content and traffic growth.
3) WordPress makes you easy to find:
Out of the box WordPress has decent SEO, it gets you 80-90% of the way there all by itself. With some additional tweaks and/or plugins, it will help your content's visibility on search engines.
4) Converting viewers into customers
With plug-ins, you can quickly multi-purpose your WordPress site to handle invoicing for your existing customers. Or perhaps you sell products and need a simple shopping cart. WordPress makes adding these features an easy process, even when commerce is an afterthought.
1) Lots of choices, Caveat emptor (buyer beware):
With WordPress's vast array of options, it can be easy to pick a plug-in/theme that does not adhere to the same level of code as WordPress itself. Using community recommended plug-ins and themes will help protect against this. But as with all things in technology, quality can vary drastically. Enable new features one at a time and confirm existing functionality when enabling plug-ins.
2) Footprint awareness
WordPress can take you a long way, but if you look ahead and can see your destination from the start, you may find that WordPress is not the best way to get there. More complex and robust systems like Drupal may be better suited to your goals. If your focus is going to be on commerce, dedicated solutions may simply be a better fit than layering plug-ins.
3) Updates can break plugins/themes
Updates are great for security! But plugins and themes that are not widely used or well written can have issues with the changes. From time to time it also happens even to those modules that are well written. Just be prepared for any custom code to need adjustment and tweaking over the life-cycle of your WordPress Site.