T., I've been cleaning houses for years. Swiffer wet or the Swiffer spray mop solution leaves a film on floors and yes, they will look dull when they dry. The film also attracts dirt when the floors are dry.
I use a microfiber mob and Pine Sol on all the laminate floors I clean and they always look great when I'm done. You can also use white vinegar and hot water if you'd prefer a more natural product. You can use Windex and a microfiber mops for a quick dusting, but I choose to use Pine Sol or vinegar when mopping kitchens and bathrooms as Windex does not have any antibacterial qualities. Cotton fiber mops also work well, just be sure you get one that you can twist and wring out or your floors will be really wet and will have to be dried with a second mop.
There are companies that make special spray cleaners for laminate floors, you can go that route if you want, but it's just a more expensive way to do the same thing you can do with natural or fairly inexpensive cleaners off the shelf.
Happy mopping!
G.