This is especially true if you mash since mashing creates a lot more trub than do extracts. In any case, if you use a secondary you never have to worry about whether you're racking too soon or too late. It's better to rack later than you need than earlier. This simplifies everything from fermenting to cleanup. The easier things are the more enjoyment you'll get out of it and the more beer you'll make.
Aeration contributes to complete fermentation.
Well, that's my perspective for what it's worth. It'll all probably change over the next 10 batches but right now I feel I'm getting great beer with the least amount of effort and expense possible.