I bought this so I could plug in my guitar into my iPhone (using Garage Band for recording and Amplitube for effects and amp sims) for quick-and-dirty recording of ideas.
Since I also wanted to be able to use it with my own pedal board and MIDI keyboard through Reaper with various sample-based libraries I wanted it to have two inputs (stereo) and MIDI, so I would not have to buy two interfaces: one for my phone and one for a laptop. That's how I ended up at this box and not a cheaper iRig.
It's been a true pleasure to use. I haven't had any issues with latency or the like. The sounds on my phone or laptop are excellent with no detectable noise, and it provides a cost-effective interface that also doubles as an on-the-go recorder when used with a phone.
Since Garage Band is completely free and Amplitube comes with about 30 effects/amps/cabs (after the free upgrade that comes with the product) you can enough to get started with basic tracks of guitars and drums. Amplitube also has a drum machine included and you can export-and-paste it as regular audio to Garage Band. The amps are not all fabulous, but they are good enough for quickly recording ideas.
You have to use batteries and headphones when connected to an iPhone (8). The latter was not clear from the manual, but not a problem. It does come with all the cables you need to connect to iPhones or iPads, Android devices, USB, or Macs. That's quite neat, so you don't have nasty surprises when it comes to cables. Everything you need is included, including a set of batteries.
The only quirky thing in MacOS was the permission to access the microphone. Since I had no intention of singing I selected "no" initially, which caused no sound to be heard even though I could see the audio meters flare up when I strummed my guitar strings. I had to choose "yes" to hear the sounds from the device. That could have been mentioned in the manual, but after a bit of tinkering everything worked pretty much without any hiccups or issues.