That depends of course - especially on the spectators. But of course: if you can have both, it's the best solution you can have :-) The smoke from the pyrotechnical effects helps make the beams of the laser show even better visible!
in fact, fireworks are well know, everybiody has seen them and they are a common solution at many festivities. However, fireworks may become boring if seen too often. sometimes people like to become surprised, to experience the unexpected. So adding lasers to a fireworks show is a great idea.
If an established, yearly fireworks show shall be substituted by a laser show, it is essential to find a super professional laser show company (e.g. look at Laserworld) to implement it. Small companies with only weak laser systems are very likely to mess up the show, as they cannot provide the visual impact tthe spectators are used to from the fireworks show.
So always remember to hire professional, experienced companies if it comes to important shows. Otherwise you, your customers and the spectators will be disappointed.
And yes, a laser show can be more spectacular than fireworks - if it's professionally done.