The team is very responsive when I have questions or need help with an issue that they are not familiar (or trained) about; if you can get them involved early in your project it will be easier for everyone! We've been using gtt managed services since we started working together over 5 years ago - their service has never failed us but there's nothing really wrong either so far as our experience goes :) They don't currently offer any kind of disaster recovery plan/backup solution like other providers do which would definitely improve my risk profile around this area significantly -- however all things considered i think overall its still worth considering because 1.) Its good value 2.).
Their customer care skills exceed expectations 3). It gives me peace mind knowing someone else takes responsibility should something go awry 4..