New or Used Amplifier

I put together my Krell 20i CD player, YBA 2 Pre & amp with Genesis V speakers in the mid 90s’ and am still very happy with it so I kept away from the equipment shops.

Now adding HT so I will need 2 more amp along with misc equipment. I know major advances have been made in amplifiers in the past 20 years, but if you had around $3,000 to invest in an amplifier would you buy new or used?