The bikes are chalk and cheese. The OP says he wants a “workhorse”. Whatever an NSR is, it’s not that.
Yes, SR150s are very sturdy bikes and you see them being used as workhorses up in the mountains, for example. The enclosed chain is a nice feature.
They have drum brakes front and rear but they’re actually fine and offer some progression.
The stock headlight is adequate, but not great for mountain road riding in the dark.
The pillion seat is better than that of many small motorbikes though not as comfy as those on the “mini-cruiser” bikes.
Just keep your eyes open for one. There should be a few at local second-hand bike shops. That’s where I got my old one.