Good choice on the 501
I have one in my 5 gallon and love it. I like the metal rimmed tank too, it's different, I've never seen one before.
The 501 is awesome. I always told myself that if I ever come across a metaframe tank, that I need it. Well, I was at a Swap not too long ago and there were 2 for sale!
One was a 15G ($50) with light and hood and then this 5G ($5) without light and hood, so I went with the 5G. Plus, I already have 2 15Gs, so no need for more.