The eBay blade.holders are garbage.
If all you're doing is cutting large graphics they're ok... I won't use them for kiss cutting just perf cutting.
Check your graphtec holder / blade and see how much back and fourth play the original spindle has.... Then check how much the eBay one has. Night and day difference, and it shows when cutting text / letters... They'll have jagged edges and slanted shapes.
I think the price graphtec charges is ridiculous. But I've bought blade holders from ten different people, including uscutter... They're all the same cheap one with lots.kf play.