I think Acyrlic is good for larger tanks.
I bought a glass 240 gallon.. 4 of us were moving it.. One guy dropped a corner.. broke it.
After some mourning, I bought a 300 gallon acrylic. It was light enough that my wife and I could lift it. That alone is a good reason to go acrylic on large tanks.. The 300 acyrlic was probably lighter than a 180 glass that I used to have.
I think if you buy an acyrlic tank from a good manufacturer, there's no worry about it every breaking. I would not buy one from a DIYer or unestablish manufacturer off ebay.. too many nightmare stories about seams splitting after a long time of things appearing ok.. It's better to spend extra on your tank, saves money on floor repairs later. On the flip side, if you buy a used Acyrlic tank that has been functioning for years, you're probably safe (unlike buying a used glass tank which is a crapshoot.. the guy might've had a leak and did a lame temporary repair).
Acrylic has better clarity than glass too. It may not seem like much, but you can tell the difference, especially if you have good lighting and run UV.. an acrylic tank looks like the fish are swimming in air (almost).
Downside with acrylic is scratches. But I think this is overstated. I have a few scratches on my tank, not very noticable.. Just be careful moving rocks, and use the proper algae scraper (designed for acrylic).. Also, I have heard that you shouldn't put plecos in acrylic tanks, as they will chew on it, making marks.. I don't know if this is true or not. I have never risked it.
IMO, the only downside to acyrlic is that it costs more. I'd take a smaller acrylic tank over a larger glass one though.
