Hub dynamos are much better than sidewall ones for regular use. My Shimano hub dynamo is great, the only disadvantage is that servicing is more complicated, to the point where few people like to open them up for fear of severing the electrical connection.
My experience of sidwall dynamos is a quality Nordlight2000 mounted on a solid braze-on tab and a standard Union dynamo mounted on a seatstay clamp. The brazeon clamp wins hands down; dynamo clamps are horrible, bendy, slippy things. You need to think about trailling vs leading edge mounting and the axis of the sprung loading. Vertical axis is affected by mount position and favours leading edge ie wheel rotation forces the dynamo in not out, ie the dynamo to the rear of the seatstay or fork. Horizontal axis is unaffected.
The Nordlight unit is heavy by modern standards but does not overheat.
You need a tyre with a file edge to engage the rotor. I prefer a rubber rotor to metal.
Twin wirering is more reliable than using the frame for earth. I'ce had fun and games locating poor connection on tour.

I use lights on a touring bike for short evening jaunts into town from a campsite and for fog/mist/heavy rain. These days you may get sufficient battery life from a battery LED lamp to last a few days of riding but when I kitted out, dynamos were the only way. I have ridden a few days with lights on the whole time.

LED lamps are much, much better than bulb lamps with one exception, If the front lamp becomes disconnected, the power goes to the rear and blows the circuitry. I have blown 2 rear LED lamps. You cant blow the front LED lamp this way, they work with or without a rear. If you wire your rear from the front lamp, you have a built in fuse no front lamp, no rear lamp) but sidewall generators can be wired with front and rear in parallel.