I bought both indoor and outdoor models online from CrazySales. I see now that you can also get them from a bunch of places, including Jaycar. I bought both to compare them, and I really hate mozzies so I figure you can never have enough different ways of killing them.
Both are made of light plastic that is probably easy to break if you treat them rough, but otherwise OK. The "grill" that catches the insects has gaps that seem almost too big, and very small mozzies might be able to escape, though I've only seen desiccated bodies fall through. I don't see why the indoor one is "indoor only" compared to the "outdoor" one. Both models have the DC power jack on top and you would want to keep them sheltered from rain. I use both outside under a veranda.
The indoor model is much smaller and a bit quieter. It doesn't have a "trapdoor" to seal the bugs in when you turn it off. This means mozzies that are still alive can fly out when you turn it off, so you probably don't want to use this on a timer. It also uses UV LED's that don't blow.
The outdoor model is larger with a more powerful fan. It has a weighted "trapdoor" that closes when the fan is off to seal the bugs in. This means mozzies that are still alive can't fly out when you turn it off, so you can use this OK on a timer. On shipping mine the weighted trapdoor came loose inside the unit. It was easy to pop back into place, but you might want to check it before plugging it in. It uses a UV fluro tube that blew after a couple of weeks of 24x7 running. I bought a replacement bulb from Jaycar, and you need to undo 4 screws to replace the bulb.
I'm not sure about the "photocatalyst" CO2 production. I can't see anything special, but I'm guessing the white plastic is doped with it. That white plastic is now a bit sooty, and I'm wondering if that has helped improve it's performance by giving it carbon to "photacatalyse".
The important thing is they both really work. I've seen mozzies fly into them, though it also catches other bugs/moths a bit. When I first started using it it didn't catch many mozzies, but there weren't many around. However recently they've been going great and catching lots, and I've definitely been getting less bites when hanging around outside.
I prefer the indoor one overall, because it's a bit more compact, quieter, and never blows bulbs.