Holland is probably the best place to study this because accidents statistics are presented in a very easy to see way.
This is Google Maps with accident stats super imposed over the top.
An interesting video here, not sure if the uploader is saying all of the problems they highlight disappear with a traditional road layout. Uploader also claims the junction is dangerous, yet there has not been an accident reported there since 2009
And assuming the stats are not to date, there is certainly no evidence to suggest that it is more dangerous and traffic certainly moves better.
Some other videos