We had major problems using 3-in-1 dishwasher tablets (usually 'Finish') as they never, ever, produced glasses that were sparkling, they always had a horrid glaze after a wash and looked as if we had not bothered to wash them (we are in an extremely hard water area though).
We changed to using the cheap-as-chips own brand (from Aldi or Lidl) varieties which work out at 5p per tablet and the result is astounding - bright, clean sparkly glasswear! It is, of course, necessary to use separate salt and rinse aid which adds to the overall cost but the difference is amazing.