As someone who went through grad school in CS, I don't regret my Master's-- in large part because it led me directly into the job I'm in today, which I enjoy (a startup devoted to commercializing tech developed in the research group where I was working in grad school).

I also don't regret dropping out of the program before finishing my PhD. After I finished my Master's and started pushing towards the PhD, I came to the realization that what I really wanted to do was just to build cool things, not spend my life in the publish-or-perish cycle of academia. So I stopped with my Master's, took a full-time staff position doing more-or-less exactly the same thing I was doing in my Research Assistantship except for a lot more money, and moved on with my life. And eventually got recruited to where I am now.