We bought tomato's in the RGV at as we were there for months, and don't know where they came from as they were bought at HEB which is an awesome family owned store, but they weren't noticeably better than anywhere else. Nowhere near the great taste of home grown.The report was just covering a study comparing tomatoes from the US, Canada, and Mexico; it didn't involve any other produce. I don't recall what they said about the Canadian tomatoes, but i think they ranked second behind the Mexican tomatoes.
I think but don't know that most of ours in the grocery store are green house grown. I read somewhere how they are actually green but forced to turn red by some process that I'm not aware of.