MOTU M4

I'm using this in my home studio setup, connecting two pairs of monitors, headphones and some mics and guitar.
The build quality is great, metal chasis and pots, beautiful LCD display with meters, and rubber bottom pads so it doesn't slip around.

The headphone amp drives my 250 ohm DT990 without a problem. I keep it at about 60-65% while mixing and at about 50% for mastered material and it is loud enough for me, with a lot more gain if you need it.
Sound is crystal clear, which is expected as it has professional converters.
The only thing that bugs me is that there is no volume control for output 3/4, at least no practical and fast way to do it. So switching to my secondary monitors to check the sound is a bit of a hassle.

Pros:
Sturdy build, clean converters, great LCD, two pairs of outputs, good headphone amp.

Cons:
No volume control for output 3/4

The m4 is definitely worth its price.
Build quality is really good, Encoders feel smooth, buttons clicky and responsive.
The connections aren't wiggly and usb c is perfect.
The outputs are solid too especially have 1/4" jacks for both 1&2 and 3&4 outputs.
Inputs are crisp and low latency, good enough for me to play guitar.
The screens are helpful and the headphone jack drives my headphones very well.
The asio is simple to use as well as the loopback feature.
To use this for music production/podcasts is a no brainer this fits the bill across the board.
My only issue is that loopback, line in (3&4) monitoring, volume knob and headphones all only work through 1&2 output channels. If you use your computer for a multitude of tasks, I imagine gaming or DJing would be under it- I like to route my game audio through my speakers and have voice chat through my headphones and would furthermore like to use my headphone output for cueing when Djing. However you can't have the headphones use 3&4 output channels. I have instead been using 3&4 outputs as my main audio from my computer. This basically means I can't use the volume knob which becomes another unneeded issue to make sure all my software is turned down as, again, I can't control the incoming volume on the m4. It would be good is motu allows users to pick which outputs channels are for monitoring and headphones.
All in all this device is still one of the audio interfaces out there at the moment in its price range and would recommend to anyone.

Search on youtube and internet something like "windows drivers problem MOTU". Sound popping, crackling, distorting on playback no matter of buffer size, settings, USB Windows settings in device manager (power options, disabling drivers and kepp ASIO only etc)...

Tried on multiple computers. And this is well known problem. Be aware if you planning to use it on Windows, MOTU drivers are junk.... And you can tell that it is computer or Windows problems - connected another USB to the same computer, same port, same settings - no any issues. No any issues whatever with integrated sound card. With MOTU it's like back to stone age...

Very disappointed, bought because of overhelmed positive reviews (assume most on Mac users). And even if some people do not have problems on their PC on Windows, it is not appropriated that device is working 50/50, like you are gambling...

This little black box has it all:
- amazing sound
- very “quiet” almost no noise microphone preamplifiers
- incredibly natural sounding preamps for instruments (all kind of guitars)
- very clever combination of inputs and outputs
- phantom power individually switchable for each channel
- great sturdy build (I dropped it just when unpacking, was moment of terror, but the interface works perfectly) :)
- unbelievable short latency time

I bought it for my home studio to replace constantly problematic Focusrite Scarlett 4i4 3gen (which replaced TC Impact Twin).
Using and abusing it for 3 weeks now, and it just works. Works perfectly well with:
- Windows 10
- MacOS
- iPadOS

I am using it with USB-C cable, but this device works without problems connected to USB-A port (USB 3 and USB2) - tested on my laptops.

If you’re looking for quality interface for your home studio, this one is wort to try.
I am very happy. In the last two years I changed/checked dozens of USB audio interfaces. Always was some problems - either noisy preamplifiers, or non-working drivers, or devices not working after OS update.
This MOTU M4 seems to “just work” :-) I am happy.

At this price range it's hard to beat the M4, especially for a device coming from an U.S. manufacturer (this is not a Made in China product!).

My full review can be read here: :
- 60dB of gain is more than enough, even the SM7B should work fine;
- pre-amp noise is quite low, maybe not as low as the Clarett 2Pre, but definitely not something that can be heard with ease;
- the ESS DAC chip really shines, so who needs a rather cheap audio interface without noise on its outputs and with a very low THD then this should be the one;
- the OLED VU-meters are a great addition here, probably the only interface adding such VU-meters on this price range;
- case and all knobs are metallic/aluminum, so quite nice to touch;
- all input gain & output volume is digitally controlled, this means there's perfect channel matching;
- no pops in the speakers when powering ON/OFF the interface;
- power button on the back;
- needs no external power supply, it just relies on computer USB power (tested on Win and MacOS and works flawless);
- powerful dedicated headphones amplifier (works even with AKG K701);
- full-scale TRS input plugs that bypasses the gain controls (directly connected to ADC).
- loopback virtual interfaces (made by the Windows drivers) really helps when need to record what you're listening to your computer (could be anything from a Whatsup call to listening music or to audio dubbing a video recording).

Cons:
- VU-meters are a bit slow, but the upper red light peaks are helping a lot when clipping occurs;
- 48V buttons are too close to the XLR mic plugs, when unplugging the mics I tend to press the 48V buttons with my big rounded fingers.