for one game off the top of my head... Metroid pinball, watch and here the stutter (unmissable). There are more games that exhibit this behaviour too (stutter, only slight and brief)
but 'antihaxer' is correct in saying for 99.9% of roms that work, the actual gamplay is un-hindered.. animal crossing and tony hawks are the only games that lag quite badly.
the main problem with ez4 is not the cart itself (apart from the lite version bad build quality), it's the support, this is where SC kills EZ4.
I pray this situation changes being an EZ4 owner.. maybe they could employ a new coder ???