It is true that the coaster is relatively easy but it still ends up being an hour commute each way including getting to the station, etc.
I use the coaster several times a month from Encinitas to downtown (40 minute train ride) but I often end up driving because it is faster due to the timing of whatever it is I need to do that day. The people who use it all the time I assume are more efficient than I am as far as getting there and using the time on the train to get work done – so the time spent can actually be somewhat productive which is better than sitting behind the wheel staring at the other cars.
If I were going to live north of the merge and commute to La Jolla or downtown I would definitely go for Encinitas or South Carlsbad though as opposed to going inland into CV (just personal opinion on that though). Although at peak morning times the bottleneck at Manchester going south is a bummer as is the lane ending just north of Via de la Valle. Those could be avoided living in CV, but other than those two points and the merge, the traffic is not as bad as some other places in the county.
On a different note, I think that the difference in schools is pretty small in all of the areas people have mentioned – some “score” a little better than others, but overall the schools in all of those areas are pretty good.