Once you get to the lake, both of the trails are similar. Both are unpaved and are popular with mountain bikers. The North trail is more advanced as it is a bit more narrow and has some steep sections. Both trails run along the edge of the lake bed and the cliff is unstable is some areas. This is not a good hike for strollers or small children.
The biggest difference between the 2 trails is the distance from the car to the lake. The North side is a much farther walk from the parking lot, and the walk is not very pretty. The path to the lake runs alongside the highway and under an overpass. It might be adventurous on a bike, but is not worth the trip for walkers. If you are hiking for the scenery, stick with the South side.