I used to have an 125G acrylic tank with a puffer...big, big mistake. He dragged his teeth all over that thing and really made it ugly. So I would be careful about what fish you keep in an acrylic tank as untamed said. But you really notice the clarity difference once you back to glass.
Before I sold my acrylic tank, I buffed out most of the scratches no problem. The tank was empty though and it was very easy.
Oh and I was able to pick up the tank very easily with my fiance...Neither of us are very big people. We even carried it up a bunch of stairs no problem. Try that with a 125G 3/4" thick glass tank
