We did the Grinchmas breakfast a few years back and loved it! That said, we felt like we had a really long time with the Grinch, because the place was nearly empty when we were there. We went the second week of December before the major holiday crowds hit and I booked the earliest time they would allow. I think we were the second family in the food line. So, the characters really had no other place to go!
Pending on when in December you are going, this may or may not be a fair review based on the circumstances.
As for the holiday event as a whole at Universal - maybe our best trip to Universal as a family. Again, the timing was great, low crowds, great interaction! The Grinchmas stage show was so fun, and talking to all of the Whos in Seussland was on point. The decorations were great, with Macy's stuff all over, and the big tree by the Mummy/Twister was awe inspiring. We also went over to Sea World for the Christmas shows which was great.