Ok, I just received both as a tester from Lightake, I'll make a video review at my next competition with some Melbourne cubers (if they want to) so we get a few opinions.
Now these are both straight out of the box, Maru is white (my far preferred cube colour) Gans 3 is black.
Firstly, size. Gans 3 is too small for my hands (to be comfortable with). I have huge hands, but just in case you didn't know (I didn't) the Gans is smaller (55 mm?)
I have a slight bias to the Maru just due to colour and size, however, I'll try to ignore these points.
They are both very good cubes out of the box, better than all of my cubes, and better (IMO) than most ZhanChis I've tried (including ex-WR one) so if you're going from ZhanChi to one of these, I feel it's an upgrade.
However, some flaws to go over. The Maru, when corner cutting, makes a slight click. It's a very small click but on some rough turns it is definitely noticeable. I think it's the edge inside corner mechanism doing this. This is likely something solved by breaking in. The Maru is tensioned very badly. One side can cut over a piece, another can cut about half a piece. This is easily fixed obviously. I tried both at various tensions. There's a recurring problem, the Maru seems less easily controlled. Even at tighter tensions.
A huge positive with both cubes is it seems nigh impossible to pop. I'm too scared to try realllly hard to open the Maru due to the internal parts which look easily breakable. However, I can't take either cubes edges out without loosening them way past necessary.
Once I tensioned both as I liked them, I timed some algs. I have difficultly with some moves on the Gans due to size.
I practised each alg a few times on my Zhanchi then swapped to these cubes. 10 attempts, taking 2nd best time or third best if I feel timer stop was bad.
<MU> Z-perm: 1.04 Maru. 0.94 Gans // Gans way more consistent.
<RU> U-perm: 1.13 Maru. 1.16 Gans // Similar consistency.
<FRU> Y-perm: 1.35 Maru. 1.48 Gans // Gans way more consistent.
<MRwRu> F-perm: 1.45 Maru. 1.56 Gans // Gans way more consistent. Had a lucky Maru one where I didn't lose control at all and got 1.45, but the rest were high 1/low 2. All of my Gans attempts were 1.56-1.8.
Overall I'd say Gans won. Gans was just consistently "nice" and I feel consistency is what you want in a full solve, rather than occasional awesomeness. I had faster for 3 algs on Maru and only faster on Gans for one, but my overall mean was faster for Gans.
I was timing with keboard, easier to time with stackmat so a little faster but it didn't matter. The Gans was just more consistent throughout all algorithms, which is what I prefer for solves. I'd prefer 13 13 13 13 13 to 12 16 11 15 16. Also consistent cubes are better under pressure.
I feel both cubes are superior to my Zhanchi (and other Zhanchis) but for me, the Gans is just better. I am now considering ordering a white Gans, even though the size sucks for me. Both are harder to control than a Zhanchi, however, they both make up for it.
tl; dr. I have a preference for the Gans, even though I dislike the colour and size I received. The Maru is good enough to be my main (which it will be due to recognition problems with black cubes), but I feel the Gans is a better cube. Before you jump down my throat Cyoubx, congratulations on having a cube manufactured, it's awesome! It's my new main, and a good cube. However in this debate I feel the Gans is overall better. This is just an opinion, and strictly about the cubes.
Edit: Also, whilst I made it seem like Gans is a clear winner, if it was, I would replace the stickers with very contrasting red/green and try to get used to black. However, they are both close, so I will just choose the white cube, Maru, as my main.