"To start, I have used this gun primarily for about a year now and I feel that I am now qualified to make a review, keep in mind that I only have experience with this one model so this does not apply to any other models of the Mars series.
1- This gun is a very reliable gun out of the box, however it is quite heavy due to its CNC rails and body, however the rails are solid and made to military spec. The stock with this model is a slim stock with only enough space to fit a 11.1 tube lipo. This is quite annoying and is the first thing I replaced. Overall pretty good out the box but the main market of this gun is the techs.
2 - working on this gun is extremely simple, the split gearbox and quick change spring guide make it extremely easy to take apart. Most of the internals will hold up to a 11.1 lipo and a m170, and the motor will pull that pretty good. Keep in mind, if you want to install a GATE Titan into it, you must remove some material in the gearbox, pretty easy, just time consuming. Also, this may be my fault but after modifying it a bit, it started double feeding, again probably my fault. The gun makes teching a dream, you will never want to go back.
3 - in conclusion, this is a great gun to use and modify, though heavy, the ambidextrous controls and good balance make it ergonomic enough to compensate, one mark is that the stock battery space is tiny, however that is pretty cheap and easy to upgrade, working on the gun is extremely easy however you need to pay attention to the small but important amount of proprietary parts, it isn’t a lot, but it’s considerable, the hop-up for example, isn’t fully compatible with some other brands. However most will fit in the gun. PTS EPM’S DO NOT FIT THIS GUN, THEY ARE TO SMALL AND WILL FALL OUT (this can be fixed by taping either the mags or mag well, however the original mags will not fit if you tape the well)
TL/DR : good gun, small incompatibilities, but if you have some money to spare for modifications to improve functionality.
"Got this one a couple weeks ago, have fired about 5000 rounds through it so far. A couple of notes after initial perfect-world testing:
1. The model I received does not have the diagnostic/burst-fire system. It is a split mechbox which is pretty neat from a technical standpoint, just doesn't have the fancy MOSFET features like (I assume) the newer MARS models do. Personally, I don't mind the absence of burst mode so I don't consider this an issue... I bought it because I like looking at shiny internals, which this has in spades. Just be warned!
2. PTS mid-cap magazines (the pretty ones with the fake brass casings) seem to have a couple of issues double-firing. At first the mags fit great but after pushing about 3-4 full mags through, the fit of the mags seems to be a bit wobbly. I don't seem to have this problem with the included ICS hi-cap mag, which has a fairly snug fit and works fine.
3. During my very first session, I popped the 20A blade fuse that was pre-installed. I didn't even get a whole mag through before it popped. Luckily, there was one spare 20A and one spare 30A included in the box. I threw in the 30A and haven't had a problem since. 11.1v tube-style LiPo from Valken is what I'm using for juice.
4. The stock that comes with the carbine is different than the ones that come with the DMR/Komodo. ICS does actually mention this in their own marketing materials, but none of the video reviews I watched mentioned it. As it stands, the included stock can only fit tube-style batteries... your nunchucks or flat batts aren't going to fit in the carbine model, but the DMR/Komodo stocks should be able to fit bigger batts out of the box.
Minor issues aside, the MARS carbine is a very solid product so far. I may have giggled like a schoolgirl the first time I switched to full auto with that 11.1v LiPo. The finish is great, especially the shiny metallic finish on the rail system. The switches and controls are nice, the tension-release mechanism when switching to safe is super nice, the quick-change spring actually qualifies as "quick change", and overall build quality is fantastic. Not going to lie, I'm very happy with my purchase.