Images are from Bandai Hobbysite.
Also, GA Graphic has a series of reviews on straight assembling a few Gundam Double O HG models, from Cherudim Gundam GNHW/R till the latest Reborns Gundam. Fans who are still pondering on purchasing any of them should go and have a look.
* Cherudim Gundam GNHW/R
* Gaddess
* Arios Gundam GNHW/M
* Seravee Gundam GNHW/B
* O Gundam
* Reborns Gundam