For people trying to decide whether or not its worth it to buy a pick and place machine, here's my experience on it. Soldering by hand is okay if you're only doing runs of 5-10 boards of fair complexity. This is usually just prototype quantities or people that are building stuff for themselves. If you are doing batch runs of 200+ of the same board, then it may make sense to have it assembled by an outside assembly house. At these quantities, the prices get sort of reasonable so the assembly cost per board drops. The only downside is the turnaround time and shipping off all your components to them.
If you're doing small runs of about 20-200 boards per run, and you are trying to maintain a variety of designs that sell in these low quantities, then you should probably look into a pick and place machine. Soldering by hand, or even hand placing on solder pasted boards, is inefficient and you'll most likely start needing to hire help. This is the area that I'm in where I do batches of about 40-50 boards at a time. The pick and place machine dramatically speeds things up where I can get the surface mount components all placed and reflowed in a single day. The thru hole components require manual assembly so I'm keeping these to a minimum, mostly DC jacks and headers.
I suspect that shops catering to electronics enthusiast communities will start looking more into pick and place machines as they run into the huge gray area between manual and outsourced assembly.