IMO Acrylic Scratches to easy and I have only seen a handfull of Acrylic tanks 100g and over that didn't bow. IMO the only downside to glass is how heavy they are to move. And Acrylic tanks do split at the seams, ask the guy that was on Craigslist a few days ago
And remember it doesn't have to be Starphire to be clear glass it just has to be "low Iron" glass. Starphire is a brand name and yes the price has come down over the past year or so, it's just that most BIG tank manufacturers are a little behind on making Starphire tanks so the prices are still high. A custom Starphire is much less now then it was 3 years ago when my 200g was built.