South Hillsboro and the surrounding areas

[Steve Moody]

As some of you may know there's a large development in the suburbs of Portland called "South Hillsboro" that's slated to add something like 8000 residences of all types (mix of SFH and multis). This will expand the city of Hillsboro to possibly become the 4th largest city in Oregon.

My question to the more experienced investors out there is this; what will this mean for the surrounding areas. Mainly older Hillsboro and Aloha/West Beaverton. These areas have lower costing homes and with that, lower rents. Will a large new development push these home values down, or will rising tides raise all ships? Will rents typically stay the same, or will a large influx of new homes and multis force prices down (and/or vacancies up)?

Any thoughts on investing in the surrounding areas in general?