Available now from the Ubuntu isotracker are images for the various supported Google Nexus devices. All of these images are now based upon Ubuntu 13.04 "Raring Ringtail" components where as some of the older images were based upon Ubuntu 12.10.
More release details and other information for those wanting to try out these new Ubuntu Touch 13.04 images can find details in this Ubuntu developer blog post.
From the existing Ubuntu Touch developer images I have delivered benchmarks of Google Nexus 7 and Google Nexus 10 on various benchmarks and compared to other x86 and ARM hardware. However, with these new Raring-based images, new benchmarks will be conducted soon at Phoronix.