I had a long (2 years) experience with GATED-based routers, host-based routers, etc. What did we learn from this experience (we just have a few PC based routers now, but it's due to historical reasons and some compatibility problems for old customer's unix-based routers), is the next idea. Let's you have a few different router vendors (I mind software vendors) in the global IP network, and both have 1 bug in their software. In case if there is 99 Vendor-1 routers, and 1 Vendor-2 router, the bug in Vendor-1 software cause the total network to have a problems, will be fixed in a few days, and moreover, if the network environment (I mean routing tables, AS pathes etc etc) appear in one point of the network, it faile down surrounded routers and you should not be affected by this bug and this network circumstances. But if this circumstances cause the Vendor-2 router to fail down, and they appear at some point of the network, all Vendor-2 routerss should be affected by this bug because they are connected to the Vendor-1 based network don't affected by this circumstances. We saw this a lot of times for GATED (fortunately gated was used by Merit and this forced them to fix the bug quickly; moreover some part of the network have been isolated by Merit from us). We saw this for Wellfleets sometimes. We never saw this for Cisco because any network influence caused CISCO to crash was isolated not far from the origin. I do not defence CISCO and do not blame Wellfleet or someone else; I only tell about our experience. If your use rarely used routing program, you are affected by the network splashes from the any point of total Internet; if you use the same router as your peers and/or upstream provider, you are isolated from such splashes (if this splash cause your router to fail, it cause your peer/ISP's router to fail before). This is the major reason why CISCO totally win the ISP market for now. And this is why a lot of vendors prefere GATED to some third-party software. This does not mean it's excellent. But it makes more difficult for the network admins to choose new hardware if it's based on the absolutely new software. I'd like to prefere the flame about Wellfleet/Cisco/etc... But to prevent CISCO's monopoly or MS monopoly, you should understand better why did this monopoly appeared.
Through the world is changed every day. Alex, if memory serves you well, which ISP used Wellfleet that, as you claim, caused bums on Internet?