The sound is very different with greenbacks than a CL80 or V30 because they have a lot more speaker breakup. It is really a question of taste whether you like it or not. The positive is that the tone sounds way better at lower volumes than a v30, but the speaker is very loose and distorts like crazy at high volumes. The low end tends to be farty but aside from that, the overall tone is very creamy with a nice midrange crunch. (Great compliment to el-34s) The farty low end is probably less of a problem with a fullstack (or a marshall) but when you start getting huge volumes, it can become annoying, especially if you want a really thumpy sound. If you don't need the bass, the problem is mitigated substantially. You really have to redial your tone for the speaker, and back of the gain quite a bit because the speaker has a really thick sound. Basically, a G12T - 75 sounds like a cross between a v30 and a greenback minus the annoyingly scratchy highs you get with the G12T. Personally, I'd use a Greenback for blues, older rock, punk, or anything that doesn't require a super tight and gainy tone. I prefer using the Marshall 1960ax cab with the vintage settings on my two channel dual. I feel the cab is not suitable for modern gain tones, where I'd rather run a standard rectocab or a Marshall 1960a.