I have one, up in the low 40s at this point, however I can't comment on the solo potential since I made the character NOT to solo, and have had friends help me with testing it group potential.
I have some gripes, like the fact that it's almost impossible to chain stuff back to me unless I'm far closer to combat than I want to be when I target my friends. I hadn't planned on taking the sentinel, but I ended up doing so just so I could hit myself with my powers without running into enemy AOE range. Also the fact that no one ever stands close enough together for all of them to get hit (I suppose this is my fault for grouping with a friend who's global name includes the word 'spazz').
But even without good slotting, the buffs seem useful, and they are loving getting electrocuted back to full endurance. I'm having fun with it so far, and I look forward to seeing how it performs at 50 in some harder trails or incarnate stuff.