Good...goooood. Let the butthurt flow through you. As a developer, I wanted to chime in on pre-release testing.
Testing on Steam is really one of the best options for an external pre-realease test program. It allows you to specify parameters, limit participation, and many other things. Steamworks has a full API for pre-release testing.
Two of the biggest benefits of Steam pre-release testing:
Audience Targeting - by utilizing Steam's Hardware Survey of opt-in gamers, they can distribute based on any number of variables, i.e. Video Card, CPUs, Memory, OS, RAM, etc etc etc. Really, really good for the compatibility testing.
Bug Reporting - Steamworks enables SQUAD able to track new issues and crashes in real-time and triage them based on severity and number of affected users. It auto-collects minidumps (logs) and parses them for you. Plus, the rapid build distribution is a benefit.
Honestly, I'm surprised SQUAD hasn't switched to 100% steam and offered the opt-in to the steam client for buyers through other services. This would be a good game for the Steam Workshop for mod distribution and updating.