VEX EDR or Lego EV3 for high school robotics elective?

[mistersands]

For background, I teach in NYC. Many students in my elective class have never been exposed to robots. There is a huge variety in English and Math ability. Some barely speak English. Some have not passed Algebra 1. Others are taking AP English and AP Calculus. Because of the elective status, most students are just put there because it fit their schedule and/or they needed a science credit. Others are on my FRC team and wanted to try the class.

That said, is Lego too remedial? I am using VEX now and have the opportunity to try and switch. I find vex breaks very easily. Maybe that's just the students not taking good care of the equipment. but I've lost so many pins on the connectors for the 393 motors, not to mention that all the screws get stripped very easily. The teeth on the plastic gears break, especially on the 12-tooth gears.

I want something that will let the advance kids be advanced, and the weaker students still accomplish something. I'm finding with VEX, the weaker students are having trouble getting anything together.

Thoughts?