I've been lucky enough to spend a considerable amount of time working with the NXT, EV3 and VEX IQ. This table shows the differences between them, along with some of my opinions.
Overview | |||
| Controller | VEX IQ | EV3 | NXT |
| Year Released | 2013 | 2013 | 2006 |
| Best Use** | Building Functional robots | Building cool looking robots with LEGO parts | |
| Target Market** | Classroom, 2-3 students | Child on Christmas Morning | |
| Which to buy? | If you're starting your collection of robot parts, VEX is a good place to start | If you already own other LEGO parts (mainly TECHNIC), you can use them with the MINDSTORMS sets | |
Hardware | |||
| IO Ports | 12 either motor or sensor | 4 motor/4 sensor | 3 motor/4 sensor |
| USB Connector | micro USB | mini USB | Standard USB |
| Motors | |||
| Can be used as servo | Y | Y | Y |
| Torque control | Y | N | N |
| Small and easy to mount | Y | N | N |
| Display | |||
| Resolution | 126x64 | - | 100x60 |
| Backlight | Y | N | N |
| Buttons | 4 | 6 | 4 |
| Sensors | |||
| Color/Light | Y | Y | Y |
| UltraSonic (distance) | Y | Y | Y |
| Gyro | Y | Y | N |
| Touch | Y | Y | Y |
| Touch-LED | Y | N | N |
| Other 3rd Party | N | Y | Y |
| IR Beacon sensor (important for Robocup Jr) | N | Y | 3rd party sensor |
| Batteries | Includes rechargeable battery | 6x AA; rechargeable available | 6x AA; rechargeable available |
| Wireless | |||
| Remote | 400/900 mhz game controller | IR, requires sensor port | -- |
| Bluetooth | N | Y | Y |
| Wifi | N | With a USB dongle | N |
Software | |||
| Graphic Language | Y | Y | Y |
| RobotC | Y | "soon" (as of 3/3/14) | Y |
| Included RC program | Y | Limited | N |
| Download Wireless | N | Y | Y |
| Brick-to-Brick Communication | N | Y | Y |
| On-Brick Programming (program without PC) | N | Limited Can be uploaded to PC, later | Limited |
| Cost | VEX IQ | EV3 | NXT |
Building | |||
| Overall Ease | VEX IQ | EV3 | NXT |
| Pins | VEX IQ | EV3 | NXT |
| Attaching Motors | VEX IQ | EV3 | NXT |
| Disassembly | VEX IQ | EV3 | NXT |
| 90 degree connection | Y | EV3 | NXT |
| Compatibility | If you have any other VEX parts, these are compatible | If you have any other LEGO parts, these are compatible | |
Competition | |||
| -- | VEX IQ | FIRST LEGO League | |
| Team Size** | 2-4 kids | 6-8 kids | |
| Focus** | Robotics/STEM | Expanding classroom activities with robotics | |
Community | |||
| Books | VEX IQ | EV3 | NXT |
Purchase | |||
| Where To Buy | VEX IQ | EV3 | NXT |
| Cost | VEX IQ | EV3 | NXT |