The only complaint I have is the difficulty to insert and hold in place the negative on the medium (a little afraid of scratching). I have not yet tested with the slides, but the results of my RAW negatives are very satisfactory (a real good picture scanner is far too expensive for the few negatives I have scanned).
The lens, which can be removed, does not seem to deteriorate image quality.
A very good price / quality ratio in relation to me.