Unfortunately, I've not had good experiences with the service reps. One put a "Request for Reconsideration Based on New Evidence" into the system as an "Appeal" causing a loss of nearly 9 months of compensation for my husband. Granted, we could have left it as an appeal and waited several years, but we opted to refile. On the refile, I did the paperwork, sent in the necessary evidence and followed up until my husband's back was added as a secondary condition and his TDIU was granted.
I would say most service reps are great, but they are limited in what they can do since they are helping so many veterans.