In general I'd agree with you, but my own experiences are mixed w/warranty returns and large, "dependable" companies. One company, HP, did a great job w/a printer I had problems w/years ago. However, Dell (yes - Dell!) has been horrendous to deal w/the last two times I had repair issues.
Not trying to change your mind here, but did want to note that B&H Photo is a really stable, well respected company, and is an online retailer that I would trust w/something like warranty support (especially for a relatively inexpensive flash unit).
I thought I was going to wait a bit longer, but all this talking about it is getting me in the mood to go order the dang 420ex! If I can just get another P.O. past the controller, er, wife...
Dana