While I see sMartins point about how the game could be better without other custom clients (To help discourage botting mainly).
At this point I would quit the game if the default client was the only one, and know many other people would too, theres just so many lack of features so many accident waiting to happen, like misclicking an item when transfering it to a belt, and having it fall on the ground...that could kill you in this game, loose you the item, and the very least is a MAJOR annoyance.
The animal tool is also major time saver rather than having to manually check all in some way (which would be hard since you cant mark them like you can in amber client, best you can do is mark them by name, but that doesnt work well when you have lots of new borns and dont want to check daily....)
Mine support radius is annoying to mine without, same with behives...Crop Stages make it much easier to farm and is a nice convenience. picking from nearest trellis is nice as the hit box on clicking on a trells can be ridiculous.
The list goes on and on. But anyway amber client is back and working now so

.