I know this is an old thread, but I found myself noticing it in my post history. I've changed my opinion and would no longer recommend using Linode for a tracking platform if you are concerned with performance. I was using my Linode for just that, and switching to a Rackspace VPS/cloud server increased page load times and performance significantly.
Just a couple of details to help qualify my opinions/observations:
1. My Linode was in the New Jersey datacenter and that's the only place I've ever had Linodes, if that makes a difference. I found that the switch was worth a 100ms or more in how long it takes for a tracking link to redirect to the landing page.
2. I'm using CPVLab, not Prosper. I don't think this makes a difference here, but the thread is about Prosper specifically so I'm mentioning it.