I've never used or even seen either of these types of machines my self.
Here are a few things I might consider before sending one away .
So much depends on the work you hope to do with your machine.
If you have the option I would suggest you set both lathes up on a temporary basis and make some trial parts of the type of work you hope to make with both machines and compare how they perform. A trial may show up any issues with them as far as accuracy, ease of operation and overall condition are concerned.
From the pictures the Kart E2N looks to me like more of a tool room lathe with a possible gap bed and variable speed drive that don't appear to be on the Sophia.
The head on the Sophia at least from the outside looks like it might be a bit heavier for heavy stock removal if that is what you need.
Comparing spindle bore and tailstock taper size, and checking both machines to see if the threads you would like to cut most often are available without using change gears might be another consideration .
Having a heavy tailstock can be a plus if you are doing heavy turning and drilling large holes.
A larger spindle bore can come in handy too for some types of work .
On the other hand if you are making small parts and doing a lot of small drilling and tapping a heavy tail stock can wear on you at the end of the day if you have to slide it up and down many times per hour all day long unless it has spring loaded rollers or an air cushion under it.
Perhaps you would find away that would allow you to keep both machines and then you'd have the option of using the one that best suits the job at hand.
P.S. more info here if you haven't see it.
Karat & Kart Lathes - Kobányai Szerszámgépgyár of Budapest
Jim
