All they charge is a commission to get into the trade, $5 per standard lot. Of course it depends on the exchange rate, but let's see you want to get in EUR/USD, 1 standard lot.
1 pip spread with EFX; $6.75 commision ($5 x 1.41 rate) + $10 on the spread (which they don't make, that's just the difference between b/a) = $16.75
3 pip spread on other platforms = $30 !
So yeah I've been saving a ton with EFX, even more when I get in with no spread!