The Tucson Weekly claims Los Betos is the "best taco stand in Tucson" (according to readers).
i went to Los Betos shortly after landing in Tucson. I got 3 tacos -- 1 carnitas and 2 carne asada. The tacos were big ones (double the size of an LA taco truck) and were topped with a pretty guac sauce. The Carnitas was divine! Juicy and crispy -- I couldn't get enough. But the Carne Asada looked like high powered compressed rat ass and tasted like rodent too. The quality of the carnitas meat was higih and the carne asada was low. "How low can you go?" well this tasted like rubber erasers you find on the floor. Gross! Note I only ate two bites of the carne asada tacos....
I'm not saying I got sick from Los Betos, because I can't tell for sure, but I did have a terrible flu / food poisoning encounter within a day after eating there. I'd still get the carnitas in a heart beat but I would never feed the carne asada to my worst enemy.
Cost: Seemed a bit pricy but the quantity of food is substantial. $2.50 is a meal in one taco
Taste: Carnitas only: great.
Experience: mixed but I'll go back for the carnitas!