In my experience, posting from AstraWeb isn't the same as posting via GigaNews.
The last time I checked, AstraWeb was set up to think large articles are spam. For binary posts, large article sizes (but under 1MB) are more efficient than smaller article sizes (think 7500 yEnc lines instead of 2500 yEnc lines). GigaNews as the other premium NSP's handled articles up to 4MB just fine (but smaller servers only safely propagated articles up to 1MB in size). AstraWeb also used to sometimes think you were spamming if you posted too fast.
Someone with AstraWeb can easily test this by doing a test post to alt.binaries.test using yEncPowerPost A&A v11b (
http://powerpost.cjb.net/ ) configured to use 7500 yenc lines per article. If it passes the large article test and doesn't think you're spamming at your posting speed, I don't remember any other problems.
Another area where GigaNews excels is it can handle speeds up through at least 100mbit just fine, whereas some of the others begin to corrupt articles if you post too fast. At 5mbps or slower upstream, it isn't going to matter which one you use.
One knock against GigaNews is on rare occasions, it'll stop propagating articles posted on their server. So people on GigaNews will begin the regular chant about how they get what they pay for when in reality, it's GigaNews creating the problem for everyone else.
OctaNews was another block account server that had no problems with large articles, but didn't handle 100mbit very well. However, I think if you don't already have an account, you can't get one.
http://usenet-news.net/ is yet another, and you can get a block for as little as $2. They have no problem with large articles, and don't appear to corrupt posts. Still, since they're all relatively cheap, if you're doing a lot of posting, there's no harm to having more than one, as they all have minor problems from time to time (including GigaNews).
