35mm negatives from my archives can be scanned quickly when a print is not available with good results for informational purposes.
Quick start-up with consistently good results.
Software is easy to load and use. Scans are good enough (with a good print) to work with them in PhotoShop.

NONE. It does what it does very well.

Have used this unit for a year with my Dell desktop computer. The results in scanning documents to e-mail to clients has made my workflow very smooth. The software allows me to quickly resize documents and photos whenever the total maximum file size approaches 2meg (the maximum I can e-mail).
Very good bang for the buck.
I'm getting another one to use with my HP laptop to scan family photos for DVD albums to send to my family members out of state.