My $.02 For what it’s worth:
If you were just buying your first Arduino to learn and experiment with, I’d suggest an Uno, or compatible and call it a day. This would give you the best “tutorial compatibility.” Since you mentioned needing “the most memory” You might consider An Arduino Mega 2560. (The Mega is similar to the 2650, except it has half the memory.) Another nice feature of the Mega and Mega 2650 is that it has quite a few more pins than a standard Uno sized Arduino. (One comparison that you might hear from time to time is that an Uno will support 12 servos, while a Mega or Mega 2650 will support 48.)
Since you already know you want to use an Arduino in a robot project, it’s a matter of comparing features.
If you get an Arduino (any sort) with the standard physical configuration, (in other words–if it accepts standard shields.) You’re going to want some other stuff. I would suggest an appropriate “sensor shield” and a bunch of YourDuino three pin cables. The sensor sheilds arrange male pins in ground/5v/signal pin arrangement. So you’ll be able to plug servos and three pin sensors directly in without having to route power from somewhere else. Also, you can run the sensor shield and the Arduino off separate power sources.
But you specifically mentioned motors So you’re going to need a motor controller, or an Arduino with motor driver circuitry built in.
The Magician Controller, is an Arduino software compatible board with a different form factor. It won’t accept Arduino shields or (probably) directly mount where an Arduino is meant to. Going by the name, it’s probably sized to fit a Magician chassis, which is a low-cost 2 wheel platform. It’s got the a bunch of three pin male connectors like the sensor sheild, and a motor driver, tho 1.5 amp total is a little on the low side. It won’t work with the popular Tamiya twin gear box, for example. Also, it uses a lower power (as in ability) Atmel 8 chip, as opposed to the newer, more capable 328. You could swap out the processor for a 328 with Arduino code burned in but it’s an additional (small) expense.
The “robot features” Arduino is a more standard sized Arduino compatible board, again with the three pin male connectors, but it’s already got the more powerful 328 chip in it, along with motor drivers. No word on the current capacity, but I’d assume it’s got the same low power controller that the Magician uses. (Edit–Terry corrected me on this a few posts down. No motor drivers) But going by It’s standard size, and better processor, the RFA is probably a better overall choice than the Magician.
There are other Arduino compatible boards out there with similar features, but you mentioned YourDuino specifically. I can’t off-hand think of any that will directly handle more than two motor channels, (as opposed to servos.) So if you want 4 motor drive, you’re going to have to do add on a motor driver shield or board. YourDuino has some nice ones at their typically low cost.batteries
It’s ironic that you immediately dismissed the spider controller. It’s basically a Mega, with the three male pins arrangement AND a built in 5V3A power supply built in. It fits well with a low cost 4WD motor controller, which happens to fit well with a popular 4WD tank treaded robot base. (Rover 5.) You can also add a breakout shield to it that adds other interface options. Compared to a Mega with a sensor shield, it’s possibly, a better option. Compared to a Mega 2560 with a sensor shield, somewhat less so, but the built in power supply might make up for the lack of memory.
As for the other boards, their small size comes with a lack of pins. But if you intend to plug one directly into a breadboard and add circuitry around it, they may be a good option.
If you’re interested, I have a Mega 2650 that I’m developing code for a Rover 5 with 4wd and encoders, that I’m going to connect to the 4wd controller I mentioned. When it comes time to button it up, if the code fits, I’m going to use a spider controller–Unless Oddbot comes up with an upgraded Spider before I get to that point.
