Both are equally beneficial and it depends on the trademark. For e.g. if you want to focus on the name, then you should go for a word mark but if you have a different pattern in which the trademark is designed then you should go for a logo. Further clarifying please refer to the below logo/device mark of H & M.
Here, H & M has been written in a different way or manner and that needs to be protected, hence it has to be applied as a logo/device mark.