Don't know how many are visiting the UA Forum these days. As the apparent program of choice for those defecting from Aeroplan, you might wish to read the following thread:

http://www.flyertalk.com/forum/Forum50/HTML/010746.html

This could make the new SWUs far less useable, and almost on a kin to AC's new rules. While a wide range of fare classes appear to still be eligible for upgrading, making these bookings on the web seems to negate their upgradeability. And while UA res can access many, but not all these fares, there also appears to be a push to raise the price of the minimum eligible fare ticket.