Is there an online test I can use to see if VOIP will work well?

I’ve read several reviews with people saying a poor ISP is screwing up VOIP for them. Strongly considering VOIP, but would like to see if it’s an OK move. Also, any recommendations on a VOIP provider? Looking for it to be a "real" line for the house, as well as provide 911 services.

Thanks!

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