I considered Lake Forest, but chose Laguna Niguel over it. Most neighborhoods in LF are too close to the freeway for my taste, and some of them look pretty shady (like the ones around Carlota, Ridgeroute, and so on. The closer to the freeway, the worse they look. Lots of mobile homes and cheap apartments. I'm not a huge fan of Mission Viejo, but it's much better than LF. Just drive around there, everytime I'm passing by those homes, literally backing to the road, with all adults present during the weekdays (indicates unemployment perhaps, not a good sign for having them as your neighbors), sipping beer, with 4+ kids running on the road unsupervised, lots of beat up cars and pickup trucks and old RVs parked along the road, and the list goes on. Trust me, there is a reason why the prices there are lower than the neighboring cities.
Oh, and look up the Meagan's law map for LF, there is plenty of sex offenders usually living at those cheap apartment complexes (I haven't checked for LF, but I was stunned to learn that most of them in Laguna Niguel concentrate in those cheap apartments on Alicia, near the wilderness park and 73 road. Even if you don't have kids, it is always a good indicator of bad neighborhoods.