I have acrylic....The weight and the acrylic able to maintian the heat better....
Glass is cheaper, wont scratch, HEAVIER , and Loses the heat faster....
Plus acrylic wont crack as easy as glass will.....200+ gal of water on the floor plus losing your fish is not worth the chance to me....just my 2 cents...others ahve large glass tanks and are fine....just be careful WHO you get it from also!