Voip is good as long as you have a decent internet connection.
I've switched to these guys
You can port your existing number for free. Their basic plans start at US$0.85/mo per line and low pay-per-use rates, unlimited plans available too. Great for business lines if you have multiple lines and cell numbers you want to manage. Good support. You get a lot more functionality than Ooma (i.e. advanced call routing, failover, digital receptionist, call recordings and transcription) but a steeper learning curve. I wish I switched over sooner.
PM me if you want a referral code that gives us both kickbacks if you sign up.