If the motor is fine, it's all about the blade and whether it's square etc, usually the 'guide' can cause the tile/cut to become not so square on those cutters so spend some time making sure it's square on some scrap tile before you cut some customers tile.
If the blade isn't cutting (you should only need to put slight pressure on the tile to get it to cut, even if it's porcelain) then you need a new blade.
Other than that, it should be sound that should.
You'll get wet though - hence the name wet cutter. 🙂 (joke)
3 thats just greedy 😉 managed to burn out the trigger on mine twice with large batches of drywall adhesive but always keep a spare, it knocks out multiple batches of skim/drywall,s/cement daily and hasnt failed (other than user error 😳)