I have worked with both rads...
Personally, I think that at this point Spring Roo has much more to offer to the developer.
1) Project definition based on an effective and elegant shell -ide and standalone.
2) It uses Modular Jave via an OSGI container so it is straight forward to extend if required.
3) It scaffolds ready-to-run web apps easy to customize to your requirements all the way to production.
4) Powerful database reverse engineering for directly creating entities.
5) At the end it is pure
Java so you don't need to learn anything to start using it.
And much more...
Here there are some links if you decide to learn more on SR:
http://viralpatel.net/blogs/author/jose-delgado,
http://pragmatikroo.blogspot.com/ and
http://www.pragmatikroo.org/showcases.
Thank you
jD