From what I know the Smithy is a better version of the 3 in 1 setup and there is forum support which is a big plus.
I have seen/run one of those lathe/mill machines (Not Smithy) in person and it had one motor and a transmission to switch between lathe and mill. It was very loose and full of vibration due to the transmission. For that reason if you go this route try to get something with a separate motor for lathe and mill.
An issue and probably the reason that mentioning planning to use the machine above (With the precision parts made on it.) is it can do one thing or the other at one time but not both. And depending on the setup it takes some time to remove the vise you had on and trammed in for milling to place on the lathe tooling for turning. Then remove the lathe turning setup and replace the vise and re-tram (Get it set precisely) for something else. Sounds like not that big of a thing but is there.
One thing to consider is the new price of the Smithy Imax 1340 From what I can see $4500 to $5000. With that budget you could have two good quality separate machines. Or else with that budget could consider something beside Smithy 3 in 1 for similar price but more precision tool. For example and I just typed in "Lathe mill combo" on eBay.com to get this:
http://www.ebay.com/itm/NEW-11-x-28...694810?hash=item3ac87c55da:g:pvoAAOSwZVlXkpRW
Then there is that concern of replacement parts if needed. Smithy will have parts if needed in the future, Off brand might not.
Best thing you did was ask questions prior to purchase to get some ideas. This is a great friendly forum.
Being in Ohio where used equipment is plentiful is a bonus. Could take time and search for your equipment as part of the fun of it. Definitely search all Craigslist within trailer range for mill, lathe or used Smithy. And can search eBay with location closest to find something close if going used from there.
Smithy machines are quality and might be the best option.