What about other trackers? Open, less politicized, trackers, that aren't associated with thepiratebay.se? Or maybe differently politicized trackers associated with other organizations? While those 4 trackers are reliable and well defended against DDoS, they are also the ones that are most commonly blocked/censored/filtered by various software nannies.
I don't pretend to be a tracker expert, and actively solicit suggestions.
I would certainly bias towards less politicized + more reliable trackers.
Please post your tracker suggestions.