As someone who has used VSR (Nokia) and VMX (Juniper) I’d suggest, good luck on your plan to use servers for this sort of routing. If you want a cheap router to handle full tables and a couple of 10G interfaces worth of throughput I’d suggest you would be a lot better off with Mikrotik’s latest hardware offering - https://mikrotik.com/product/ccr2004_1g_12s_2xs
Just my 2c >We're also looking at going the virtual router route where we put 2-3 servers >in a HA cluster loaded up with 10Gb interfaces and running some sort of >routing software. In case you didn't catch on, I'm fairly early in running >this idea through the paces, although it seems like >this is a pretty common >thing nowadays.