Based on my reading of the table, the PurpleAir II sensors seemed to be the best of the sub $300 for PM1.0 (field R^2 of 0.96 to 0.98) and PM2.5 (field R^2 of 0.93 to 0.97). The PM10 readings were not as good (field R^2 of 0.66 to 0.70).
After skimming the rest of the table, it looks like the PurpleAir II sensors might have some of the best field R^2 for PM 2.5 and PM 1.0
After skimming the rest of the table, it looks like the PurpleAir II sensors might have some of the best field R^2 for PM 2.5 and PM 1.0