First off, I will tell you a little secret of mine. I do not like to write. I find no joy in it. I feel a little pretentious doing it, especially when it is to write for my own benefit.
That being said, I do not mind writing as much for a client. I believe because it is easier for me to be objective and move towards marketing the client in their best light. Not to mention how important it is these days to be able to give a little more fleshed out story to potential customers than the typical advertising venues offer. And did you say native content?
Blogging is a great way to do this for your client. However, one of the things I see most is people who blog for clients with very cookie cutter copy. Not every topic is so dynamic and new that it gets its own unique perspective. However, I feel if you are going to do a blog, it does need some customization. Every business has people and things unique to it. That is why I like to include quotes from members of the staff or special things that make the business unique.
This is not always easy to do. A lot of the topics I write about have an immense presence online already. It is hard to figure out what to add to the conversation when it seems it has already been said better or with more depth. What those articles don't have though is the staff of the business I am writing about. They all have their own takes on the products and services you will write about. Talk to them. Quote them. Bring in a perspective that no one else will have. Position your client as the experts they are in the field they are in.
Believe me, someone is always going to wax poetic better than you. There are some great bloggers out there. However, blogging for content is not a "Who is the next Hemingway?" contest. Simply look around the business you are writing for and talk to people. They will give you the elements needed to make sure your blog is not generic.