Domain name changes in Google SERPS

Is a 301 redirect enough to maintain position?

[borisbaloney]

Changing your domain name (even with 301 redirects from the old domain) has been blamed recently (since the "sandbox" arrived) for the loss of good Google SERPS.

Before that it was generally accepted that moving your content to a different domain and redirecting it, would result in maintained SERPS positions with only a brief changeover period. The links from the old domain would be credited for the new one.

Has anyone attempted a domain name change like this recently?
If yes, what were the results?

With link age considered by some as a heavily weighted factor by Google, is a 2.5 year old domain name now best left alone?