Some useful stuff in the article below - it's all about focusing on length, quality, depth and reader experience rather than writing lots of short articles. I agree with a lot of what the author says, but as a reader of lots of content, I can't help but think that there is a place for the shorter comment or opinion based piece as well (like this one....)

I travel to work on the bus, and find that this is where shorter articles really work for me. A bus journey is full of interruptions and it's hard to focus on a single article for a long period of time. Shorter pieces allow me to read up on five or six topics on my way to work.  

Ultimately though, it really depends on your readers, and more importantly, the people that read your blog and ultimately convert into customers. There is plenty of data at your disposal to help you work this out and I think it's important to make sure that you are able to offer the sort of blog posts that they want to read.