Intrusion Detection Systems for Gigabit Networks?

caelyx asks: "I've got to evaluate various IDS solutions for use on a gigabit network. While I've had experience using and configuring snort, I haven't used many of the commercial solutions (Dragon, RealSecure, ManHunt, etc). I guess I'm mostly concerned with signature quality and depth, the power of the analysis console(s) and a robust engine that won't drop packets on a busy network. What experiences have Slashdot readers had with various NIDS or hybrid NIDS/HIDS solutions? Suggestions?" Ask Slashdot last touched this topic in this discussion, but it didn't focus on the needs for a Gigabit network. How well do the solutions mentioned therein perform on such a high end network?