I often wonder what people did before we started bottling and injecting O2 into our beers. I guess we probably didn't make too many of them? Are "big" beers a new-ish phenomenon In the beer world (so to speak?). I ask myself that question along a lot of similar type queries, like wort chillers, etc.
I am getting an O2 system myself for the record. They seem pretty affordable for how long they last, and how much you can potentially get. I find too often it is my mashing and temp control that really has improved my attenuation. I wouldn't toss money at an O2 system until I had perfected that first.