Picked this up three days ago with big expectation, especially for the B-model. Based on the pictures I've seen on the 24h Car I was unsure if I should buy it or not, but the B-model made me do so. I started building the A-model and got VERY IMPRESSED. The model is much bigger than I thought, very sturdy and it was an amazing 5-6h build. The next day I took it apart to build the B-model which I was looking forward to. My expectations was higher than the result and I actually got a bit disappointed. On the other hand, I am really satisfied with the A-model so I just finished building it again.
For all of you who's not having the 42039 on the store shelves yet, save your money because you will really want this one!