I had a Shimano NX-30 until this year, which has been replaced by the newer Shimano DH-3D70. My daughter also has the same, and I also have two Schmidts. There are a few real-life differences between each one of them, so here is my take on it.
Minimum speed
As you said, the Shimano dynohubs get your light at full power at a slightly lower speed than the Schmidt. But the difference is minimal, so it's a moot point. With the Schmidt, you'll get full power at 7-9 km/h; with either Shimanos it will be at 6-8 km/h. To be clear, let's say that if you ride at 8 km/h with a Shimano, the light will be bright and stable; with a Schmidt, the light will be almost as bright and will flicker a wee bit.
Friction
The old NX-30 had a noticeable level of friction, both on and off. Nothing to complain seriously about, but I could feel that the bike was less lively when I used the dynohub wheel vs a standard wheel (same tires). Most importantly, the wheel felt a bit "rough" when the light was off and I was riding at 25-30 km/h; no such feeling if I rode slower or faster than that target speed. When the light was on, I definitely felt some pulse while riding the bike. It did not bother me for commuting in the inner city (stop and go traffic), but I'm not sure I would have liked it if I had been riding long distances at a constant speed, like when touring or commuting in suburban territory.
The newer DH-3D70 (or DH-3N70) is much smoother than the NX-30 and also has less friction. I
know it is not as efficient as the Schmidt, but I can't feel the difference. Nowadays, it's hard to justify a Schmidt on that factor alone, unless one has odd spoke requirements that are only satisfied by a Schmidt.
Durability
Here, Schmidt wins hands down, especially if one cycles year round. I bought my first Schmidt and my NX-30 in November 2001. Both have been used year round, including in the snow – the Schmidt for longer rides and the NX-30 for commutes. To make a long story short, I had to scrap the NX-30 in the Spring 2006 because it was tight and worn out. The Schmidt, with about 25-30 000 km, still works like new.
No idea how the DH-3N70 will behave, but I suspect durability issues. So if you plan to ride a lot in rain, sleet or snow, the Schmidt will be more durable. On the other hand, if you store your bike in the fall and only get it out next April, then get a DH-3N70.
P.S. If you want to save some money, follow Sheldon Brown's instructions for
wheelbuilding. That way, you only need to buy the hub and new spokes (20 $ extra). That was how I could make the Schmidt semi-affordable.
Lights
All the headlights Peter White sells are designed for the road. In your case, I would recommend the E-6 which is both very visible in the city and also very effective on pitch-black roads. The only limitation is if your MUP looks more like a winding foot trail: in that case, the E-6 will throw light straight ahead... which is not what you want in tight bends.
I complement my lighting with a cheap Planet Bike Beamer 5 blinkie which I fire with 2 rechargeable AA batteries. It's a decent be-seen headlight which still works when I'm stopped, and the flashing mode is sometimes useful in business districts. You might also use such a light on your head and point it around bends on the MUP.