Especially if you sit in front of a computer, you can find quite a lot of documentation about it on the web. I'd bet that, if you want a car, first you do some homework to figure out if you want a compact or an SUV. Same here.
I do not have any direct experience with a 10E. I believe that it is the lighter model, with shorter stroke, optimal for fine work and finishing. Less optimal for hogging through several thousands in a hurry.
The only Biax scraper I'd consider too specialized, handy mostly only for hogging, is the 7ESM (it's also a few lb heavier than the 7ELM).
But, overall, the question is if the machine is in good shape or not.
As far as the price goes, I believe that $750 (if it is in good shape) is a fairly good deal and, if I hadn't any ethical constraint (the machine has been offered to you) I'd have sent already a PM to kensmachine.
Paolo