My local phone company ad a service called " remote call forwarding". I could roll it to my cell or to a phone bank who answered it as if it were my receptionist.
The problems I have been having with Google Voice is some of the calls being made to me are not coming through. Instead the caller is getting a busy signal. I have been told this on too many occasions.
I use a voip service that allows you to set up all kinds of rules for forwarding, including follow me and setting number of seconds the phone will ring before going to vm - which is great for forwarding to your cell because it can stop just shy of going to your cell phone's vm and instead revert back to your business vm. Best part is you can set a rule to send marketing calls or any phone number you want to lala land. Never rings or goes to vm, just deal air. It's the least expensive service I could find. Problem is, I'm affiliated through a referral program and can't put their name out here. Add your email to your signature block and post back here if you're interested.
I use grasshopper. The only thing I don't like about them is that they don't have a service to send faxes, only receive. Sucks because I have to pay for a separate service to send faxes.
Try MagicTalk or SkypeIn. I have both, but primarily use Google Voice (originally GrandCentral). How you set it up is important. With MagicTalk you can choose vanity numbers as well. Great for signs... xxx-CASH xxx-SOLD XXX-SELL for example.