Another DVD-r DVD+R question; emtec dvd+R in US?

Hello. New member here. I have enjoyed reading lots of posts, but my head is about to explode. I am looking for DVD’s for long term storage. Yes, I have read the “long-term” storage threads. I have read a lot about the +R format being superior to the -R format in several respects. But, most of the “archival” grade DVD’s seem to be in the -R format, and what many consider to be one of the “best” DVD’s, Maxell BQ, is also -R. Any reasons for this? My other question is that the Emtec Gold DVD+R is highly recommended by a very knowledable poster on these forums, but I can’t seem to find those selling in a US based website. My plan is to save my critical data (photos, etc) on both formats. Since I don’t need that many discs, there is no reason not to use both. Any help with this would be great. thanks.