AllWinner A20 are mainly interesting for the Cubieboard2 (a community card like raspberry pi, but more powerfull) that is one the reason of the work on AllWinner SoCs, and the OLinuXimo (open source hardware).
The vanilla mainline 2.11 already boot on A20, but SMP is still not managed. User still need to use linux 3.4 and add the allwinner patch, instead of the mainline kernel with patch submited inside by the community.
This processor is not really powerfull, but powerfull enough, to (with opensource drivers), be used as desktop env or like nano-server (NAS with the SATA port, or web server for personnal use or few visit site for example).
And CedarX is the only one on low cost dev card able to decode 4K HD video (still to be add in os drivers).