I wouldn't say very close when there is $2k difference, more like they're in similar price range, anyway as I mentioned before 300B is hard to beat, it is one of the best sounding tube, but for whatever reason if you need to get a new pair of tubes, it may not for better sound quality, it can simply because the old tubes dies on you, and when you try to get another pair it is quite costly, let alone to say that you are after better sound quality, it is something that one have to take into account, but to be honest, does the envy sounds great and better than Nirvana? I bet it is and I like it, but will I try to get my hand on one? Most likely no, I've owned a 300B amp long time ago, don't wanna spend another fortune on one again.