My next upgrade will likely be a 225 or 300g, I will go acrylic.
Why?
1. Going bare bottom, less prone (not immune) to scratching.
2. Kids in the house, I can see a hot-wheels hurling across the room hitting the tank. This has already happened with the neighbors kid by the way, I ended up with a pretty bad nick on the tank, but it didn't shatter. Buffed right out with help from his dad. Hard to say if a glass tank would have survived that one.
3. Easier to drill after the fact. Needs change and I like the flexibility.
4. Optically clear.
5. Thermal abilities in the winter, although with MH not too much of a problem.
Anything smaller than a 180g, I'd go glass. My 180 is acrylic and I'm looking forward to buffing it out completely and essentially ending up with a "new tank." Or I might just upgrade, we'll see.
PS. Good point on the black car analogy, but just like a black car...when you take the extra time to wash and wax regularly, nothing beats the look of a clean black car. I feel the same way about acrylic.
Here's an idea, construct a tank out of acrylic and coat it when a thin layer of Starfire glass. MONEY!!!