We heard mixed things too and felt the same hesitation at first. In Lisbon, we mostly walked and used Uber/Bolt and that worked well for getting around.
We did try a tuk tuk experience, but not in Lisbon. We did a private tuk tuk tour in Sintra instead and that’s where it really made sense for us. More space, less traffic, proper stops, and time to actually see and understand what you’re visiting. Our guide was Daniel Ponce from Yes, You Deserve!, and it felt much more like a guided experience than just being driven around.
Personally, I’d use Uber or Bolt in Lisbon and save a tuk tuk tour for somewhere like Sintra, where the setting really suits that kind of experience.