When I started RP'ing as a main 'play-style' instead of treating the game and my toon as an extension of myself, it was only a few months until FW hit. By then the IGS was quasi-horrible - loads of the bullshit and sucky things we got to day, but also plenty of quality interactions and topics, ATL in my opinion. A mix-mash of both I soon found the trick to reply with quality to what I and my toon found interesting to reply too (The two had to match up, obviously) and had loads of fun conversing with people regarding topics of interest. It slowly went down-hill after the launch of FW, for a variety of reasons, but I still recall that core part of the IGS' activity and participants that was worth dealing with.
Then I stopped playing repeatedly and went inactive, then Incarna hit, and now the IGS is at it's low ebb, with questionable quality the only quality to remain, for the most part.
In short, the "IGS is worth your time" era died off some time ago, far as I know. Opinion may differ on if it's truly gone, when it died, and to what extent.
Personally I'm more worried over lack of IC news, events and lack-luster treatment to some PF elements.