My company did a pilot of Happster, Officevibe and Culture Amp. Each product was fantastic in its own regard but Happster came out on top for us. Officevibe has really insightful weekly blog content which is how I found them. The stunning graphics on their marketing materials is really quite different from their web app. Quite honestly it required an unnecessary amount of hand holding, its not the most intuitive platform. My department, amongst others, had some difficulty getting started, which lead us to look at some other options. Culture Amp is really cool because of how flexible it can be. The downside for us was that although detailed and impressive, the results of the survey come in as a lump sum making it hard for our managers to take meaningful action. The lack of action perpetuated an environment of distrust between our leadership and employees.
For us Happster was the perfect fit. We did encounter some hiccups with the dashboard (bulk on-boarding), but their team was very accommodating in helping us get rolling. I generally leave Happster open on a tab of my browser all day because of how useful little features in the dashboard are. It's only been 2 months but so far we have already seen a decrease in turnover!
*Ease of use.
*Backing from the Psychology world.
*Extra features like "to-do's"