They are definitely softer, and made of poorer metal, with poorer heat treating as well, which will very likely make them flatten or crumble with smaller hammer hits than higher quality ones. You gotta be more gentle with them or they will let you down. All transfer punches need some care in their use.My Spellmans/Spellmaco came used off ebay. Decide if you need throughs or blind or both.
Please take note of Bob Korves observation. I've not used an import set.
I've heard they tend to be softer. Might not be true. Don't know.
Daryl
MN