CurveHouse.com has a nice Home Networking 101 article explaining the options for full-home networks.
They point out that "Ethernet cable remains the best solution for anyone who demands speed and consistency", but your need the "wherewithal and the ability to competently perform all that is required to hardwire" your home. And while "Theoretically, wireless networking is the perfect answer to the hassles of Ethernet cable", but "wireless networking is erratic.".
The feedback on HomePlug was "we experienced no glitches, no delays, and no dropouts", but your mileage may vary. MoCA is "theoretically and, in our findings, practically superior" to powerline, but "is nearly twice as expensive".
CurveHouse.com got all this right, but at the end of the article they stopped thinking with the "G.hn: The Best of Both Worlds?" question. G.hn has a MoCA like RF feature, so the cost will be simular to MoCA. So when you use G.hn powerline, since it has RF, it will be "is nearly twice as expensive" as the HomePlug device.
Also, why wait for G.hn, when HomePlug based products are available today that work on coax, powerline and phoneline.