edit: Okay so it's webkit based, mac only, with built-in adblocking, which sounds nice, but honestly the idea that it can easily install extensions from both chrome and firefox sounds like a security nightmare to me.
The fact that the only mention of security in their FAQ is to conflate it with privacy
"Most browsers regularly "phone home" dozens or even hundreds times. Each request poses a security risk"
is a red flag IMHO
Full text for reference: "Each request poses a security risk, no matter what information it sends, by potentially exposing your IP address and your browser fingerprint. Telemetry can also inadvertently leak personally identifiable information or corporate intelligence."