Here are the major differences:
1080i deinterlacing: the ABT 1030 discards half of the vertical resolution with 1080i because it lacks the processing power.
MPEG Noise Reduction: Reduces the sparkly noise around text/borders, as well as blocky artifacts seen in motion scenes.
Detail Enhancment: Sharpens regions inside an object border, such as pores on a face
Edge enhancement: Sharpes the edges.
(BTW, 3 and 4 are very effective as they don't produces halos/ringing, although detail enhancment can slightly increase video noise, but not too bad.)
Frame Rate Conversion: 60p-24p or vice cersa for film sources.
Pretty much the ABT 1030 is a simple SD Scaler/Deinterlacer, while the ABT 2010 is a full fledged SD/HD video Scaler/Deinterlacer and Processor. Same as found in the $799 edge and $1299 Duo.
If you have a 1080p capable TV, I'd highly reccomend the 2010 (AVR 2310)
over the 1030 (AVR 1910)