We haven't missed our 5GHz target with our Core i7-7700K yet, and thankfully the Gigabyte Aorus Z270X-Gaming 7 got there too. It needed a bit of coaxing, though, requiring 1.38V and a dose of loadline calibration to remain totally stable. This may well improve with the latest BIOS version, though, which we haven't had chance to try yet. Thankfully, this didn't result in off-the-chart power consumption - it remained at reasonable levels, even under load, although the stock load power draw was a little high.
While Gigabyte hasn't quite improved the EFI to be a slick, responsive experience like that you'd get from an MSI or Asus board, it has added a few tweaks. However, its software is vastly improved. EasyTune and the System Information Viewer along with Smart Fan 5 are excellent, with access to a host of voltages and clock speed settings as well as the multiplier and RAM settings too.
The fan suite is particularly useful, as you can calibrate the fans you're using in order to have full control over their speed ranges - you can even turn them off below certain temperatures and set an alert if they stop spinning unexpectedly. Gigabyte also bundles a blue light killer feature, an OSD overlay function, plus smart mouse and keyboard features that are similar to Asus's. The RGB lighting control - RGB Fusion - is detailed and easy to use as well.
As we mentioned above, the fan control section of the EFI is much improved, and there's also the most advanced EFI-based RGB lighting control we've seen as well. However, the EFI isn't as responsive or clear as the competition still. That said, with such great software, plus the fact that it's still easy to find the usual settings, this isn't a massive issue, unless you'll be spending a lot of time in the EFI.