rico soul: I wanted to post some more photos of the kit from various Chinese reviewers, and also give a bit of a comparison of this kit vs the AoBing. (TLDR: buy the AoBing if you have to pick one)
These MotorNuclear kits seem to be getting the most international upcharge from how much people are interested in them. Their internal Chinese marketing put this entire line as one of the highest value model kits with the retail price set at a low $199RMB. By comparison, the Infinite Dimensions Genesis was a more premium price from set at $238RMB and $298RMB for the regular and collectors editions respectively. While the current pricing here on Gundamit is still fair when compared to Bandai gunpla kits, I wouldn't say it's as much of a must buy for everyone as the previous $65USD price tag on the AoBing. Still, if you are interested in this line then this CaoRen is certainly still worth pre-ordering. I placed mine already.
However, if you are unsure and just want to try one MotorNuclear kit, go with the AoBing instead if it's available. The kits uses very similar approaches, with the runners being partially pre-painted for color separation details, and some highlights being in clear plastic for effect. And of course both comes with that alloy internal frame. The AoBing being the first in the line also comes with a colored manga/manhwa in Chinese to help establish the lore for these suits. the CaoRen does not come with this.
The main body of the kits are very similar in shape and structure. In the first comparison pic, that's the CaoRen next to the special coating version of AoBing. Both standing at about 20cm tall. Aesthetics are individual preference, but I tend to think the blue on the AoBing looks a bit more interesting than the mostly white CaoRen
The main differences in the kits really comes down to the backpack and accessories. The AoBing comes with a standalone dragon that can be combined with main body in several different ways or displayed separately. The CaoRen really comes to life with it's backpack, effect wings, and phoenix transformation. Still, in this, the AoBing simply offers a bit more ways to play with. For weapons, the AoBing has two polearms, the CaoRen comes with a sword and shield, and the tails of the phoenix can also be held as whips.
Now for the main unique draw of this kit, the Phoenix Transformation, I think it's a great looking transformation but it's a bit of a parts formation. The main body structure is pretty much the same as the AoBing afterall so there's not really any built-in transformation, but it's also not going to be loose like transforming gunpla tends to be. The legs fold up towards the head. The backpack breaks into wing and tail sections, and the wing parts attach on the legs while the tail attaches behind the head. The hands are replaced with phoenix and the arms becomes the phoenix legs. The separate phoenix head attaches at the crotch and the mobile suit head is just left hanging as the butt. It looks good overall but once you see the upside down robot head, it can be a bit silly. But this is the same way the metal build worked originally.
Both kits were based on the older 1/72 scale metal builds, but both have seen some updates aesthetically and are high quality model kits. It will be interesting seeing how the BaiQi turns out in model kit form which was very similar in design to CaoRen except it was yellow and transformed into a western dragon.