SS, on the button pushing thing, it's unlikely that anyone is personally familiar with that aspect of the two units, so you might simply have to endure the suffering of trying to compare the two manuals. The 525 would have a little more maximum power capability, which wouldn't be an advantage unless you're exceeding the 601's capability. The 525 does have individual crossover settings for three different speaker groups and you should decide whether that's a significant advantage with the speakers that you're using.
