On version 0.7.1. GRIS seems to sync only for the oldest news that is still kept in the reader, as a result, despite that I have maxed the number of articles to be synced (500), I can only get news that is posted 28 days and 29 days ago.

Wow, that's a lot of feeds. I can add an option to sync newest-first. Should it also display items newest-first in that case?

(still, that is by my calculations about 7,500 unread items. Which is a fair few more than standard usage ;))

that actually lead to another question that i have: is there any way gris could check to avoid duplicate articles? Most of the articles I am syncing from Google Reader are duplicate but are from different sources (feeds). Thanks!

Not really - that's way outside the scope of GRiS. Maybe try yahoo pipes or something similar?

There should be definitely done something with this issue. Huge amount of articles is not non-standard usage! Imagine Google News Sci/Tech RSS feed http://news.google.com/?ned=us&topic=t&output=rss which has about 100 articles per day. I have already 1000+ unread articles after a few days and there is no way to catch-up with all. The workflow is to just see the newest ones, quickly scan through headlines, choose only few from them to read and let the rest be forgotten even if they are unread.

option added in 0.3.3 - if you turn on sorting newer items first, the download behavior will also use this setting and download the n newest items.