I did an unfunded MA, but that was at an in-state school where I also did my BA. I didn't want to teach (stupidly) because I had a job that paid better than a TAship, took less time, and ultimately that allowed me to finish in two years rather than three like a lot in my cohort. I sacrificed teaching experience for shorter time to degree and made more money doing so by paying in-state tuition and not taking the crappy TA stipend.
So I guess you could look at "unfunded" as a chance to get finished with your MA more quickly, thus paying less tuition. However, if they offer tuition remission beyond two years, it's worth the teaching experience if you intend to go for the PhD. Unfortunately, I'm pretty sure my lack of teaching experience is hurting my chances this app season... (ironically, the job market favors publications over teaching experience when it comes to tenure-track jobs).
Just my two cents.