Always have atleast one backup you can switch too Incase your main service goes down. There is no best iptv service, what you do is try a lot of them out and see for yourself on your own network. So go on YouTube and do some research and good luck.

Really depends what you're looking for. I resell Primestreams that specializes in US channels, sports, and reliability.

However a good place to start is /r/iptvresellers . I'd recommend getting a few trials and see what fits your needs.