I've had the Echo for about 18 months. I'm a EE and can share my feedback:
1. My previous wired brake controller was fine but I never used the override other that testing. I travel through mountains frequently, my previous Highlander weighed about 3800lbs and my loaded Aliner folding RV weighs 2500lbs.
2. The Echo kept me from mounting a brake controller in my new 2018 Highlander under an already-crowded dashboard, locating under-dash wires, fishing wires through firewall, and difficult installation.
3. The Echo calibration instructions are vague. I'm still not sure they're exactly right.
4. Echo uses the Aux+ and Ground return to power it. Test your Aux+ to see if it automatically turns off when TowV off to avoid
battery drain. If it doesn't, unplug Echo during extended stops.
5. Even without BT connection, Echo indicates working with on-board blinking
lights (hidden normally with 7-way cover). That's usually all I use unless I'm REALLY board.
6. If not well-plugged-in and well-secured, Echo can unplug and will be damaged by dragging. Avoid this by providing back-up support wire, string, chain, or wire tie. Mine is now slightly damaged but still works.
So far for me, the advantages outweigh the disadvantages.
I hope this helps.