Improve over 4.0, which was completely and utterly unusable. I still have my 3G, so I can see what it is daily. A 4.2.1 3G is generally slow and laggy, but for the most part it works (as far as I'm concerned anyway: all tapbot applications run acceptably, Instapaper, Wikipanion and Terminology work and so do most — though not all — of my games).
Not saying it's great, or even good (compared to 3.1), but that I can use my phone is a net improvement over 4.0, which had essentially killed the bloody thing.
> In particular, the new Facebook app appears to be unusable on the 3G nowadays.
I wouldn't know about that. I have no use for facebook's application.
My own app FemCal, runs pretty well on 3.1.3 on a 2G, but I think almost everything is a struggle for iOS 4 on the 3G.
In particular, the new Facebook app appears to be unusable on the 3G nowadays.