I've been thinking a lot about the kind of nests and outworlds that appealed to me as a beginning ant-keeper vs. now. I think the biggest difference is I no longer like "all in one" designs. When I was getting started these kinds of designs seemed easier, especially if I thought I might need to move the nest and outworld... but really, disconnecting the tube isn't such a big deal (unless it's a species that stings)
The real issue I have with many all in one designs is they do not have big enough outworlds. Not even close. Take a look at these designs:
Should you have a colony that can fill those nests spaces those tiny outworlds are going to get trashed in just a week! These outworlds will be crowded with ants and it will be annoying to remove the lid and clean.
In the founding stage many ants don't need an outworld, then small colonies are so shy and cautious they will only need a small feeding space... but everything changes once the colony gets into the 300+ range. Your ants aren't shy anymore. They want to explore. The outworld should be several times larger than their nest. This might mean having multiple outworlds.
The only downside is it's hard to find large outworlds. Everything seems to be geared for smaller colonies.
The other downside to "all in one" nests are the limited viewing angles. By definition the colony will block part of your view of the outworld. It will be harder to see both. So, beyond the late founding stage I think it's mostly better to skip all in one nests so you can better customize the ratio of outworld to nestspace to match the needs of your ants.
What do you think?