You're really asking the wrong person here. Because again, I'm not in the market for paying that much for a home. If you were to ask me which would I prefer, the lexington one or the PH. I would take the lexington one, because of the view, sqft, lot size,etc. I don't care about being the first "new" owner. Others may differ.
In general, I wouldn't be spending 1.6 on a home because I don't need it. I have 1 kid 1 live in nanny and occasional relatives that spend the weekend here. 5 bed/3 bath place with a decent room is fine. I don't need a bonus room, entertainment room on top of a family,living,dinning room. Everything else is nice to have. You have to ask yourself if you really need so much room, or need the view. If you go down to say 3100-3500sqft, you have a lot more to work with. There are places in Torrey Hills like Montecito, La estrada, sea country that would be a step down, but around 3100-3500sqft and probably considerably less than plan3. Also, you can consider Breakers which is next to Derby Hills. Plenty of my qcom friends live there. It is still has access to ashley falls elementary. (for now). It still isn't cheap, but there's more competition in this price range. The only thing you have watch out for if you live in Torrey Hills is don't by a home near power line. You shouldn't have a problem unless you decide to buy in Sea Ridge (not Sea Country) or the community behind Sea ridge (forgot the name). Ranking in "niceness" imho from greater to less… Lexington, Breakers, Sea Country, La Estrada, Montecito. You might also opt for a plan 1 or 2 in Derby Hills. View lots are a premium, period. Doesn't matter what plan.