I shoot a lot of Provia but not Astia. I don't really like the look of Provia pushed, although I have pushed both the 100 and 400. The grain is okay, but the highlights have a tendency to lose detail rapidly even if slightly underexposed (1/3 stop). The last time I did this was for a boat show where I ran out of E200 and had to resort to Provia F 100 rated at 200. Believe me, the highlights took a real beating compared to the E200 rated at 320.
E100G and E200 can be pushed really well as they have long shoulders & hold highlights. E200 should be rated at 320 not 400. 100G holds up pretty good at a full stop push of 200.
I've pushed both Porta 400 to 800 and Portra 800 to 1200. Both films push really well. I did aerial photos with the 400 pushed to 800 and the prints couldn't have looked better.
More good color films available today than anytime in the last 35 years.