I did a little research and while I was surprised to find that as unmanned transport et al have been saying, the Trent gets worse fuel economy compared to other engine options on the 777. But I was even more surprised to find that the Trent is considered the most RELIABLE engine on the 777 and that the GE90 777 engines have actually had more problems and require more maintenance hours per flight hour.
Interesting flip of what I would have thought.