I did look on ebay every day for many months on end to find these like a woman obsessed, you need to be ready to pounce
The very best thing is how predator proof he Omlet coops are (foxes have been trying to get in for years without luck), how easy to move (I've moved a Cube with a 4 metre run attached to it over a bumpy field on my own), and how easy to clean. Plenty of ventilation, too.
I only have Cubes and Classics, though, can't speak for the Go.
We sited ours on top of 1/2 mesh so rats can't dig under, and used tent pegs in case of strong winds.
Never had anything gnaw its way in. The seller of the first secondhand Cube we bought did point out where something had tried to chew its way in, but whatever it was hadn't succeeded, didn't even damage the plastic much.
All the panels come apart and can be pressure washed, and it is really easy to find, squash and spray red mite. In our garden the coops are all firmly screwed together but on the field the coops are all inside a large fox / rat / stoat proof run and we've just slotted the panels together. When red mite strikes the coops are treated in literally under a minute.
They're not perfect, for example on the Cube, the nest box and the door handle are on opposite sides, and the pooh trays are taken out at the back with the coop door being at the front. So you need space around every side of the coop, you can't put it against a wall. The Classics would have been good on a frame with wheels, but they're not and given our lack of skateboards or similar so we just drag them.
There are a number of brackets that allow you to slightly adjust them to the ground the coop is sited on and make sure the rainwater drains properly.
Siince our garden isn't perfectly flat, one coop has dropped a bit in a corner making the roof more difficult to open. So we could adjust the roof bracket slightly so that it all opens and closes easily (except we keep on forgetting to do this as it's not a big enough deal).
I never looked at the other plastic coops, I just like the design of the Omlet coops so can only speak for those.