Much worse, I'd expect. I doubt their porting work does all that much with power management. And there's no GPU driver, so whatever power state it starts up in is what you're going to get.

Also they seem to be booting Ubuntu off of a USB stick, so it's possible that they haven't figured out how to support the internal storage yet, let alone things like audio, suspend/resume, ethernet/WiFi, keyboard/trackpad (for the laptops), etc. So those things would either come up completely shut down (and give you better power stats than you'd expect under normal usage), or come up active, and possibly not have power management enabled at all, killing your battery.

Edit: looks like in the last half-day they've just figured out PCIe, the USB-A port, and ethernet: https://twitter.com/cmwdotme/status/1352361874076164098?s=21