I am planning to implement an employee engagement or pulse survey this year.  What product are you using?  Please share any feedback regarding the product.

Last year we started using Quantum Workplace for our engagement survey platform.  We have been very happy with it.  They have IO psychologist that help you build out the survey if you want to do more than the standard survey questions.  They also have the capability to do pulse surveys through their system and managers can have access to the results if they have 5 or more employees.  The feedback from leaders since we changed to this vendor has been extremely positive.

We use a Workday product called Peakon. It has a great question bank, you can send a longer annual survey, weekly surveys with few questions, or something in between. The analytics are great as well. I highly recommend this product if you are a Workday customer. 

We are currently using WTW 

We use CultureAmp for biannual global engagement, pulse surveys, and employee lifecycle surveys. We subscribe to the People Science+ service which provides an extra level of connection with their organizational psychologists. Overall happy with the service and the tool.  

I've had the most in-house experience with Lattice and found it to be a robust, comprehensive platform for employee engagement/experience. The data and insights provided have been really helpful for identifying issues and action planning throughout the employee lifecycle. The eNPS/pulse surveys help us track leading indicators and flag issues before they become significant, and the more thorough/qualitative engagement surveys allow us to really target action plans for managers to increase engagement and retention. 
When consulting, I've also used Culture Amp and Qualtrics and found them to be great tools as well - just haven't had as much in depth experience with them.