Some of my experience with the Nomad.
Yes, it is mid-heavy. This can work for or against you, depending on the situation. Alone, the mids can be kinda harsh, in a band setting, all the mids do really help with cutting through the mix. I was able to hold my own against a deep snare drum that had the most delicious upper-mid *Crack!* to its attack, and a Marshall JCM2000 TSL with dimed mids, through a 4x12 with Vintage 30s. I did so with the mid knob turned only halfway up and a scoop dialed into the graphic EQ.
Channel 1 is a circuit similar to the preamp you might find in a blackface or silverface Fender Reverb amp. Granted, a similar circuit does not a Fender make, so if you want Fender cleans, get a Fender. That said, the Channel 1 Clean is a very good clean. Good for pedals, or good for just a straight up clean tone, as warm or bright as you want to dial it.
Channel 1 Pushed is a very fun mode. A couple resistors and caps are moved around in the circuit and it can now be overdriven, depending on how high you set the gain. Pushed can go from a cleanish edge of breakup all the way to a nice medium to medium-high gain crunch. The tone controls are pre-distortion in this mode, and can really shape the tones you're getting.
Channels 2 and 3 share the same portion of the preamp circuit. The circuit is similar to what you might find in a hot-rodded JCM800 2203 preamp, or in a one-wire-mod JMP 1959: three cascaded gain stages and a cathode follower driven tone stack. A few capacitors and differently tuned tone stacks are all that really separate the two channels.
Channel 3 sounds kinda British to me. In my band, I was getting similar tones to my other guitarist's Marshall, but fatter and a little deeper, especially with the scoop dialed in on the graphic EQ. It it tight and fast. I mainly used it for my main distorted rhythms. I never used it for metal, but I suppose it can be used for metal, depending how much gain you need/want. Despite channel 3 being the brightest and tightest of the channels, it won't get up to Recto levels of gain without starting to feel kinda mushy in the bass. If you want that much gain you'll want some kind of pedal to boost with, or another amp.
Channel 2 is voiced with much more low mids and bass than channel 3. So if you like channel 3 (as I did) channel 2 will probably feel bloated and clumsy. If you like channel 2, channel 3 will probably sound thin and harsh. I never found a use for channel 2 that I fully liked. I tried using it for edge of breakup sounds, but it sounded too dark to me for those not-quite-clean tones. I tried using it for high gain leads, and the smoothness of the channel does make for a nice contrast against channel 3, but I kept coming back to channel 3.
An aside, Vintage mode in both channels 2 and 3 only switches in a resistor into the signal path after the tone stack to darken the channel and quiet it down a bit. It does nothing to change the actual voicing or gain structure of the channel otherwise. You might find such useful, but I found it too subtle to be of much use.
The reverb uses a solid-state circuit, so it isn't that big tube driven reverb one would find in a Fender. It still sounds just fine, at least on channel 1. On channels 2 and 3, it is very subtle.
That's all I got for now, I'll post more later.