I sent the same email to them, but I did get a response:

We're fundamentally different than Zenefits in a few very important ways, so accessing all of Gusto's features still makes sense: 1) Payroll is your system of record in your back office and quite simply, we believe computers follow rules a lot better than humans do. Zenefits functions on a “hub-and-spoke” model… they’re the hub, we’re the spokes. But that's already an outdated functionality-- there should be no spokes when it comes to payroll and benefits—they are really just one single hub functioning in unison. Removing the spokes and human operations that Zenefits uses removes the opportunity for error.

2) We’re a customer service organization, not a sales organization. With the technology comes the vital human touch—you’ve got your dedicated Care Team trained to support your benefits just like you have a Care Team trained to support specific payroll needs.You also have your dedicated and experienced Benefits Advisor for business and benefits strategy planning. This way, you can go to one partner for all your back-office needs rather than using an intermediary to control several different disjointed resources.

3) Because it’s all in one place, you get one beautifully simple experience for your entire team—administrators/managers and regular employees. That means onboarding your employees' payroll and benefits in one place while we help you navigate the confusing world that is US Health Care Reform. Basically, we love you as a customer and we want the best product experience for you. That happens when you use the full Gusto platform to combine payroll, benefits, and compliance.

It wasn't very convincing to me, and I think it might be an even harder sell now that Zenefits is launching payroll. I love both companies but I definitely would prefer to have everything integrated in one platform.

fwiw, we've had less than a great time with Zenefits, whereas with Zenpayroll, we've been amazed at how good they were. They helped get through some tricky payroll business, and were always quick to make sure everything was in order.

I'm happy to pay the money and get the faster response times, better website, and stronger relationship with ZP (errr Gusto).

We'll probably move off of Zenefits entirely soon.

Same - I'm actually starting the process of switching over the Gusto simply because I wanted to consolidate the services I was using, but now I'm having second thoughts since Zenefits is free. So far I much prefer the Gusto/zenpayroll interface, so I'll probably keep going forward with Gusto and only switch back if I run into any frustrations.