From the provider that I use (ACE IPTV) I was able to copy their M3U playlist onto my Openbox V8S and stream their TV channels. The V8S comes with the WebTV app.
However, when I loaded the playlist it did not display the channel names. I know it is possible to get the channel names displayed but I didn't spend enough time working through it to understand exactly what manual edits were required to the playlist.
In summary to answer your question, I believe that any IPTV provider who offers a playlist will work on a V8S. However there are many better options than a V8S for streaming IPTV.