If the project is ever completed, it should be beneficial to the owners of co-ops and condos on the upper east side, particularly those on first avenue and york avenue. It was just announced that there are futher delays though. If you are planning on buying in the area now, and counting on the future subway to increase the value in the short-term, you're probably better off looking someplace else. Of course, if you want to live on the upper east side, and plan on living there for several years, then you should reap the benefit of the second avenue subway in the long term.
I think it will make a huge difference since now a days everyone does not want to walk and live close to the subway. Before, years ago. Living near a subway was considered a flaw, not welcomed and property was devauled because the subway.
Before all of those prices go up, they will probably drop once construction in the immediate area starts, I'm assuming the building is on the same block, like 69th street, 96th, etc...In the long hall, say 10 to 15 yrs for everyone who purchases in the near future and can hold on to the property for that long, it will be a huge benefit. In New York its all about convenience, how well are you situation, how accessible is the area, and what is near you. Someone said for a short term investment, you wont make much, think way long term.
Which Condos have you seen already?
As to delays, they are to be expected. Another big but less known project by the MTA, called the East Side Access, is being worked upon out in Queens. ESA will allow LIRR trains to also terminate in Grand Central, which will immediately improve the value of most of NorthEast Queens, but especially express stops like Woodside, Bayside, and Douglaston. Especially Douglaston, where the schools are good,the lots are large, and there are nice water views. When I first heard about it, the expected completion date was 2008. No ESA as yet, now the date is 2013.....if the funding comes through. I'm about 1/2 mile to the Murray Hill local LIRR train station, with other transportation options like the Bus to the Subway if I need to get into NYC, so I am not holding my breath or relying on it being done anytime soon. Frankly, I don't think it will finish until 2020, probably the same time as the Second Avenue Subway, so if you have a 12 year horizon, then great. If not, then it will be a nice perk if and when it ever gets done.