Using an older model Deskwriter, I have observed that Driver 3.9 does not render font shapes as well as 2.2 did. In addition, Excel 4.0 hairlines (horizontal) will sometimes not print. (Sometimes even 2.2 will skip a hairline or two.) If I didn't have SuperLaserSpool, I would surely miss 3.9 Print Monitor but I have found myself switching back to 2.2 now and again.
I have discussed this with both Hewlett Packard and Microsoft but to no avail. I will be sending them an example file so see if they can fix the hairline problem. I don't know what to do (or say) about the font shape issue.