Better than efax is RingCentral. You can get an 800 number with multiple voice mail boxes plus the number doubles as a fax number. It can also be used to receive or make calls, but that costs extra and I haven't used it yet.
We have had persistent bugs and inconsistencies. By itself, this wouldn't be a huge issue, but their level one support is untrained, powerless, and seemingly reluctant to help. In all my support calls to them, they have yet to put me on the phone with someone who understands my problem and has the power to fix it.