I really love the tank and think it's well-suited for moss and shrimp. It's so short that getting adequate flow is no problem. And lighting? Even this cheap-o eBay LED fixture I bought does the trick.
Bonus of the AC20: way more media options. You can even run a standard bag of Purigen if necessary. Parts are cheap and readily available. More sturdy than the Red Sea Nano (which is a great filter for standard 2.5gal tanks).
You'll likely need to cut the intake pipe with a Dremel tool or hacksaw but that's the only real modification necessary. I also cut part of the intake strainer down so I could pull the sponge up a bit higher.