In short, my question is what are people's opinions about mills and lathe units, versus combo mill/lathe machines? Are there any advantages to having units separate from one another?

I would like to get into machining, but I don't want to spend thousands of dollars and have something that could be more capable if I had purchased a different unit. I know that this is subjective, and depends on what I am looking to manufacture and how much production I would like to achieve, but I would still like people's advice (in general). Is a combo mill/lathe just better all around, or are there advantages to having separate machines?

Thanks,
J