Toaster ovens that don't heat to the des...

This week we have bought and returned 3 different toaster ovens because the actual temperatures in the ovens at different times were (a) extremely different from the knob settings or (b) wildly inconsistent. We tested them with two different oven thermometers that agreed with each other. We spent about 2 hours with each one, giving them lots of time to settle out and see what they were going to do.
One oven (Europro) was 50 degrees over the setting at all settings. One (Black&Decker) was 20 degrees over at the high and low ends and dead-on in the middle. The third (Black&Decker convection oven) would heat up a little past the setting temp and then drop about 75 degrees and stay there (about 65 degrees below the setting).
What's up with this? Are there any good toaster ovens?
Thanks