This rings true for us. We're a small company who would've blindly walked into zenefits if they had simply walked us through our enrollment process smoothly. Instead we had repeated paperwork glitches which always left out a few of us (from a very small group already) employees out of the quote/enrollment process.
We started looking at Trinet in parallel and to our astonishment found that the comparable health plans, from the same provider, available on Trinet, were significantly cheaper... (as in ... ~30%) for our situation. The Zenefits glitches were really a blessing in disguise for us.
(The key to these discounts was that with Trinet you're getting into a group plan... while Zenefits simply enrolls you as individuals if you're a small startup).