Not quite, i've alway shopped between revzilla and competition accessories (compacc). Compacc have comparable prices to revzilla and will price match revzilla price (likewise for revzilla, rezilla will price match compacc), but you have to make a call. Compacc gives higher cash back value for purchases, so the better deal is compacc because you get the same price (if both stock the item) and compacc will give you larger cash back bonus for next purchases. Revzilla does have larger selection of gear, nicer website and better user review section.
I'm curious about the tax thing. If you live in PA you should be charged tax because sale tax applies to purchases made within state where they have a store or distribution center. So even if you live outside of Philly (if in PA), you should be charged tax. Are you within PA? At least enjoy it while it last because the government is not happy about not getting in on this interstate online purchase thing. Many laws are in the pipeline to change this. Not only does uncle sam want in on the profit but it is also due to brick and mortar stores like best buy that feels online sellers like amazon have the upper hand for not charging tax to out of state buyer.
