The first reason is SEH is in San Marcos and that is one reason it is discounted. Second it is farther from the 5 and the ocean which makes a big difference in your commute downtown or proximity to shopping and entertainment. Although now that Twin Oaks goes through to San Marcos it is not as big of a deal. Third, most people have bought in SEH not because of the development but because it is cheaper therefore the owners are weaker financially than those who can afford the coastal zones so expect more foreclosures and fire sales in SEH. This of course is just my opinion and I have no hard facts to back it up. Worse than SEH is Discovery area on the north side of the hills SEH is in. If you want a good deal your best buys are there if you just want a big home cheap. I would buy in La Costa or Encinitas before SEH if I could afford to, as it is I will barely be able to afford a nice home in SEH and only if they go down another 100k or so.