Highly Recomended!
This is definitely a fun project to #3D print and assemble or it's available with the 3D printing already done.
It works very well with the many already loaded programs that are pre-installed. I dropped a couple of stars on the
"Documentation" window as I feel it could be a little more clear as how to use the various programs BUT this may only be because of MY 77 year old heads inability to understand it. Regardless, it didn't matter that much because any questions I sent off to Ken were answered very quickly and precisely, elimating all my concerns.

Now to start on making my own programs. I'm excited!
Be aware Ken, you've been warned! HaHaHa

Instructions were a little confusing because there were several documents describing each of several revisions to the hardware, but otherwise sufficient. Preloaded sw was easy to modify without reading documentation.

My only gripe is that I haven't been able to make the pen up/down servo work correctly (I haven't reached out for help yet due to my own time limitations; I'm not criticizing the vendor's support). Fortunately my pen is locked in the down position, so my son is still entertained by the drawings produced by the robot.

There is something about a physical robot putting pen to paper that excites and stimulates young minds more than the prettiest graphics on a screen could ever do. Amazingly, there is a huge "hole" in the robotics market to serve this purpose. OSTR stands alone, but is by no means a compromise.

The electronics kit is straightforward and easy to assemble. The parts shipped are packaged correctly and the components chosen are easy to differentiate and assemble. The instructions on how to assemble them are also organized well and the order of assembly is correct for making sure that the parts are easy to solder (short components first, etc.). We have not used the IR wall detection yet, but this was a very nice touch which helps give the robot some additional educational opportunities.

The 3D printed body shipped is also very good quality. I was nervous at first because the holes for the metal nuts were not well shaped, but I found that pressing the nut into place by sticking the bolt through the hole, then threading the nut on to "pull" it into the plastic and finally removing the bolt, leaving the now-captured nut in place worked very well. The wheels also fit on to the motor shafts perfectly. I don't think that the "grub screw" method in the documentation would have worked at all with these wheels at all, but thankfully was unnecessary. The instructions also recommend threading the (long) motor and servo wires under the chassis but I found that this caused considerable interference with the movement of the pen.

The overall design of the robot is very well thought out -- putting the four AA batteries as low on the chassis as possible gives the robot a great low center of gravity and also adds considerable weight which helps the robot move around on the paper. The robot is pretty robust and other than it being stepped on or falling off of a table, I would not be worried about it being man-handled by excited children. I found that calibration was largely unnecessary, especially given that dead-reckoning movement is highly inaccurate to begin with. We were printing simple designs in only a few minutes. I think that adding a few washers to the caster so that it helps keep the robot from "rocking" would improve movement even more, but we really are talking about finicky little details.

There are only two "downsides" to OSTR, and neither prevents me from recommending this to anyone. The first is that you must connect a cable to the robot to program it. This is however easily solved with any of the BLE-to-UART modules that you can find online. The other downside is that for younger kids, programming the robot in Arduino's IDE is a little challenging. I am looking to see how difficult it would be to use any of the Blockly-inspired GUIs to program the robot with any tablet or computer.

OSTR really is a wonderful, relatively inexpensive Turtle Graphics robot. I would absolutely recommend it to anyone who would like a basic drawing robot platform.

(Please note that Tindie doesn't let me not rate the communication; I did not try to communicate with the business owner but could not mark this field "not applicable")

Robot kit assembly was fairly easy and straight forward. Robot works as it should and is fun to do turtle graphics on paper rather than on screen.

The Turtle Robot is a good first tech project for anyone wanting to learn more about programming Arduinos, electronics, 3D printing, CAD and design. It gently guides you through each step to complete the project step by step. It also gives you enough information and access to modify the programming to explore further. If you have access to a 3D printer, I suggest you buy the kit minus the printed parts. Many libraries not have 3D printers you can use for free, including plastic. Check you local library.

The weak point on the robot is the wheel design. The spooks are thin and the center hole is a little too big making them loose. This is a perfect chance to also learn a little CAD by importing the files and modifying them for a better fit. I also drilled the stepper motor shafts and tapped them for a M3 screw where the wheel holes are. Putting the screw all the way through the motor shaft makes a very strong connection.

The link to code to test the LEDs in the documentation is missing. It would be nice if the code were put back on GitHub.