We were using Zenefits, but we switched to ADP. We ran into some scalability problems with Zenefits. ADP is the market leader and they are a very stable system. The UI, unfortunately, is not as good.
Yesware features are divided into two big categories: the first set of features is for the individual salespeople to improve productivity: manage drip campaigns, email analytics, integration with phone, calendar and CRM. The second feature set is for managers to figure out what opportunities are people working on and get an overall view on which sales are most likely to close. More than 60,000 software and media sales people use it every day. It’s great for startups. Try the free trial at www.yesware.com