We rented a tandem kayak for 2 hours using a Groupon. The staff was quick to help and knowledgeable. The kayak, life jackets and paddles were all in good shape. They have a good selection of other rentals include a swan paddle boat which looked like quite a bit of fun. They also offer food at the snack bar but I didn't get a chance to try any of it.
Lake Wingra is a bit small so it is perfect for a novice or those who just like to paddle around in a relaxed manner. If you are looking for more of a challenge then this may not be what you want.
There are plenty of other outdoor activities right here so it would be perfect for those who are looking to have a full day of activities: boating, swimming at the beach, walking around the zoo and using the new city bike rental kiosks.