Nextvision N6 HDTV Scaling

[QKRTHNU]

If using a (W/S)XVGA monitor w/ a Nextvision N6 to scale/convert an HDTV source which will look best (assuming you have the option):

First - Which is the best up-scaled 720P option:

1280x1024 or 1280x768
- Obviously the aspect ratio is different 1.25 vs 1.66, but when the N6 does the scaling is there any Real visual benefit going from 768 to 1024?

Second - Comparing 720P up-scaling to 1080i down-scaling:

Which will look better?
Down-scaling a 1080i source to 1280x1024
or
Using the better of the two up-scaled 720P options from above?

Thanks