Interesting document by Sony discussing the topic of mixing tape brands and the whole tape lube issue:
http://pro.sony.com/bbsccms/assets/files/mkt/recmedia/solutions/hdvtapelube.pdf

I have always stayed with JVC tapes so I haven't had much experience with head clogging problems other than a bad section of tape here and there over the years. Is it just urban myth then? I wish it were more of a 'white paper' detailing the testing methods, tapes and results. I guess a take-away for me is I should clean my cam's heads more often than I presently do.

Yep, there's already a discussion on this over in the Tape forum.

Here's a direct link to the thread:
http://www.dvinfo.net/forum/long-black-line/470815-wet-vs-dry-tape-lubricant-controversy.html