Just seeing this... for a schematic, we have 30A and 50A examples posted, plus editable versions:
Schematics – BruControl
In terms of cost, when it comes to a DIY panel, the basics are the same: enclosure, power feed & distribution, contactors, breakers, SSR's, receptacles, wiring, etc. The main differences are that for dedicated hardware, you need 2 or 3 PID's and a timer, whereas for BruControl, you need a microcontroller and the software. Quick look seems to show PID/timers run around $40 each, so for 2x PID's and a timer... $120, and $160 if you want the extra PID for temp reporting of your third vessel. You also need hardware switches for accessories like pumps... so maybe those are $10 each. Needs LED's and buzzer, so maybe another $20. So added up, that's $200.
For BruControl, you could use a simple Arduino MEGA and a screw shield for the microcontroller (interface) - these will be about $30 total. Assuming the connection tot he computer is Ethernet or Wi-Fi, you will need a shield - these run about $30. If you If you want to use RTD sensors over 1-wire, each probe will add about $20, so say $60. You'll probably want a relay board to handle switching pumps and other accessories. These run about $15 for 8 channels. Software is $170 for the Advanced version. So added up, that's $275.
So the hardware difference is about $75 (rough estimate), assuming you already have a computer for BruControl at your disposal. Would be almost nothing if not using RTD probes. The dedicated hardware requires more drilling/cutting and wiring, so there is more labor there that offsets this, depending on how the builder's time is accounted for. If you are super cost sensitive, this difference may matter, but in the context of the overall cost of the panel, it's a small percentage. And when aggregated into the full brewery, it's practically negligible. However, the main consideration to think about is the future path. With dedicated hardware, you are essentially dead-ended. Any upgrades will take a dramatic re-build or modification. With a software based approach, you have almost limitless upgrade options, especially if you plan for it in this initial build. A MEGA has ~45 I/O... so that could be 45 PID's, 45 switches, 45 sensors, etc... So if you are building in stages, or potentially want the option to develop further in the future, you have the flexibility.
Another miss with dedicated hardware is data logging and reporting. For example, no graph of your temperature history to see aberrant temps and swings. The other difference is automation. Dedicated hardware has no automation options. This means no mash ramping, no boil-over protection, no sparging, no pump control, no valve control, no volume or flow measurement, etc. When you add motorized ball valves to a rig, it makes it nearly 75% automated. And automation does not mean the brewer isn't brewing - just driving consistency and efficiency.
I personally think anyone building a panel today using dedicated hardware is truly limiting their brewing potential, but I realize there is relative safety in doing what has always been done in the past. In fairness, if you don't like the idea of BruControl and its application cost, you could take a look at other software based solutions like CraftBeerPi - a Raspberry Pi is ~$100 and the software is free. Support is only community based there, but the hardware side would save some money.