Our family has owned Vernie (Lego Boost Creative Set) since it came out. We have an extra set of the 'brains', Boost Hub, Motor, Eye, and an understanding of how the iPad application intends on guiding you through the build and challenges. We also have two iPads to allow for independent builds. You need all of these things to build and control two simultaneously. But, to unlock all of the missions you'll need to do one at a time or scrape together substitution obstacles.Simultaneous Build Pros:- Each Droid can be built and controlled entirely independently. (we had a double build session)- Only need a few common pieces needed to install two hubs simultaneously.- With two iPads, kids can swap which Droid they can control to complete missions independently.Simultaneous Build Cons- Accessory kit for missions is shared. This is huge bottleneck.Having the other Lego Boost set gave me a good understanding of both the programming language and Lego's design language with the application. The kids really enjoyed the immersive portions, the cut scenes, the characters, the missions. These are steps you need to accomplish to get to all the features of the droids. It also helps to understand the missions (just make Gonk punch 20 times, easy). And an understanding of how the color sensor and distance sensor work (R2D2's search and map needs to see Yellow and Red to pass). This allowed us to use old Legos to mimic the shared pieces to push through the bottleneck of not having multiple accessory kits. We haven't swapped motors yet, but swapping out of R2D2 looks difficult where out of Gonk is very easy.As a single kit, this kit is awesome. We loved Vernie and are comfortable with coding in the boost language. I was worried that nothing would compare to R2D2, but Gonk holds his own! The Droids are much larger than you'd expect (though my six year old pointed out smaller than on the box).The kids built their own unsupervised, so from time to time something wouldn't align. The ability to rotate the 3D model to check their work and solve any issues isn't possible with a paper book. (I've torn apart whole kits for single misalignments). We like the paper books, but the guided build does work well.The R2D2's ability to turn his head, go slow upright and fast with lean, then snap between the two is really endearing. It's difficulty for me not to steal these for my own collection! As an adult, the missions are tedious, and for kids (mine are 6, 8 years old) they still need guidance to see what the goal is. But, after doing them once you can totally 'cheat' your way through if you understand them. The programming language is simple and fun, especially if you use the sensor (walk up and shoot Daddy). The kids mostly just use the audio functions endlessly.There are many comments that the kit is expensive. However, considering the application the motor and the piece count, this seems like a high value to our family.