The OP didn't say where he is located, used machine tool availability and price varies greatly by location. Here in this part of Idaho machines are few and far between with much higher prices than other parts of the country. I just upgraded from a Atlas/Craftsman 12" benchtop lathe to a free standing 80's vintage South Bend 13". I had to drive over 500 miles roundtrip to fetch the South Bend back from close to the Oregon coast area. When I see the machines and prices on the Portland, OR Craigslist I have to keep a roll of paper towels handy to mop up the :drool: Guys in other parts of the country buy nice machines for scrap prices.
The Atlas/Craftsman is a good learning machine. I made a few parts I have used while building stuff for my tractor. You find the limitations pretty quick as far as 'speeds and feeds'. It is light duty and can take light cuts, this is fine, just takes longer to get things done. The belt drive is nice because when you screw up the belt just slips

Single phase power so you can just plug it in an go. I added an AXA quick change toolpost to it and that helps a lot in speeding up your work where tool changes are involved. No quick change gear box which really slows you down when working on something where you want a slow feed for a nicer finish but then need to switch gears to thread etc.
While the 13" South Bend is still belt technology it is light years better than the Atlas/Craftsman. Three phase power but I got a rotary phase convertor with it, took a bit to get things wired up. I can take much, much heavier cuts than with the Atlas, so far I haven't been brave enough to find the edge of the cutting envelope

This one has the 1 3/8 through hole in the spindle and camlock spindle. The bigger the through hole the better. It does have a quick-change gear box which is nice. Spindle speeds are still low by today's standards but fast enough for me.
Practical Machinist and Home Shop Machinist are both good resources to read about various machines, just don't ask questions about Chinese/import machines on Practical Machinist... they are a banned topic.
Do your research and don't be afraid of Craigslist. Just beware of the guys who think just because it is a lathe or old or 'South Bend' or whatever that it is gold-plated under grey paint

You have to do some research to find out what prices should generally be for your part of the country. Tooling gets expensive fast so the more you get with it the better.