Quality of the replacement glass in doubt?

Of all the replacement ipod touch glass screens around, i am going to assume most of them are of similar make and quality (coming out of china), just with different sellers.

When i first attempted to replace the screen, i cracked the replacement glass whilst inserting it back into the frame. The LCD also leaked. In comparison, the glass previously was cracked so bad throughout, and the glass was missing in places, yet the LCD was not damaged.

At the edges, the replacement glass is flat, whereas the old glass seems to be slightly rounded.

Does this mean that the replacement glass is of much less quality and thus more prone to cracking?

Sorry this is not much of a question, but i cannot find this anywhere.