Not knowing who NTI is, I had a look on their Company Profile:
NTI released the world's first CD Copy software in December of 1995. NTI's full line of software products have been recognized by: PC Magazine, EMedia, Smart Computing, PC World, Five Star Review, and ZDNET.com. PC Magazine's famed columnist John C. Dvorak commented on NTI CD-Maker: "This software is close to perfection!"
So I guess they are okay.
Do 'you' know by experience?
I don't have a good experience with NTI tools, at least with some of their products a few years ago. I had NTIBackup 3 or so, and their CD burner too. They messed up almost each update, the new build installation usually failed or rendered the software non functionning.
NTI shadow was ok though. So my advice would be to test before purchase.