Even before the Linode memory upgrade, Linode was more competitive for many uses because they offered 32 bit systems, whereas Slicehost only has memory-hungry 64 bit systems:
Good catch, I didn't realize that. Before writing my article and switching to Linode, I politely asked if that was going to happen any time soon, but they said no, and the rest is history. It took them, it looks like, over a year to add that functionality.
http://journal.dedasys.com/2008/11/24/slicehost-vs-linode
After the ram upgrade, Linode is a clear winner. I just hope they don't screw up the good service as they gain customers.