A few people complained about the balance shifting and getting betrayed by the Nexus groupmates, but that has never been my experience.

The problem, as I remember it, was a time period when at the hero level there were one or two squires, a warden, one imperial and five Nexus. The balance tipped toward the light, and so for a month there was this sick gank squad working with imperials almost exclusively.

I've played a few nexans myself, and my biggest complaints were 1) no bondmates, and 2) everything balanced.