Originally posted by Shaitan
Generally speaking you want to control your workers. The AI does a decent job of selecting things for them to do but it's far from optimal. The automated workers will also not gang up on a project. For example, say you have 12 workers and it takes 12 turns to make a railroad. The AI would accomplish this by sending each worker out to work on a separate tile. In 12 turns you would have 12 railroads. A human player would pile all 12 workers into a work gang and complete a railroad tile each turn for immediate benefits.
That said, I'll generally automate with Shift-A when my rail network is complete and all of my in use tiles are developed. I don't see a need to micromanage busy work.
I have found a few "problems" with automated workers. The most frustrating is, they tend to waber off through other peoples territory yo get at cities you have on the other side. This can destroy your rep, tho slowly, if the other civs are always yelling at you to remove your workers. They will also road and railroad ALL tiles in your territory, tho the unused ones will be done after the ones used by cities. This can be a waste of work.
An automated worker will often do a tile here, run accross the map, do a tile there, then back again. This isn;t too bad once you have railroads, but before then, they tend to spend too much time in transit.
When you conquer a city near your others one, the automated works will rush in to improve it if your other cities are done and the captured city is in need of improvement. This can be dangerous if there are still enemy units in the area, the workers are bound to be captured, or you must 'waste' units protecting them.
Another nagging problem is when you have lots of workers on automation, and there is nothing for them to do. The inactive workers go to "sleep" in a city. EACH turn, each worker will "search" for soemthing to do, usual all during the "auto-move" section of the turn. If you have a large territory, and 100+ workers, this can take quite some time. They will be "marked" then as having been moved, so if you want to move them, you have to wait a turn. There is no quick and easy way to "un-automate" a large number of workers.