I've been with Battlelog a month now so here are some thoughts...
I started with Warzone Supreme and was more than happy with the product. After a couple of weeks I wanted to upgrade to Warzone Premium and this process was made easy with the support staff here, particularly a guy named 'Celestial', he took a few bits of information and upgraded my account quickly and easily.
I'm sure everyone here is familiar with 'Frost13' - this guy has been awesome to work with in resolving issues and answering questions. In addition, the whole community seems cool and friendly.
You get what you pay for - In my time here, whenever there's been any kind of downtime, I was notified and informed that we're compensated. Downtime has always been minimal because the staff here updates the products frequently and quickly, and it's a small inconvenience given how great the products are.
If you're on the fence or undecided about trying Battlelog - don't be. I've been gaming and involved in many communities like these for over ten years, Battlelog has been one of the most well-run and reliable that I've seen thus far.