I have WPMU DEV Pro, and I will likely use them for as long as I build and maintain websites.
I have the dashboard installed in approximately 75-80 sites across two separate accounts (one personal and one business).
I love their plugins, their blog posts, and their support. This is a great suite that I personally love.
There are a few people at work who claim some other options are better, but it's really hard for me to see their point. Their discretion is the only reason why we don't have hundreds of sites with WPMU DEV yet - but we're getting there ;)