Oh, the endless debate with no real "right" answers...
In my opinion, based on research and advice from various sources, I think a high-quality dry kibble supplemented with fresh fruits and vegetables is the best way to go. Dry kibble is better than wet since wet is mostly made of water. Dry kibble also is better for the teeth since it helps to clean as they eat.
As for Grain-free or not, I still have no clue! I think as long as they are "healthy" grains (i.e. brown rice, barley, potates), and are not an extremely prominent ingredient on the list, then it should be fine.
Having said that though, I just switched my girls to Orijen which is a grain-free formula. I rotate days between the 6 Fish and Chicken Adult. I decided to go with orijen since, in my area, it is the highest quality food that is available. It is made in Canada with human grade meats and although it is also the most expensive available, I really do think it is the best on the market. I used to feed Fromm four star but their forumla has TINY pieces, which are basically swallowed and not chewed therefore have no teeth cleaning benefits and they eat it quicker. If you feed grain-free though you will have to cut down a bit on the quantity.
I used to supplement with salmon oil as well, but now that I'm feeding the orijen 6 fish I think theyre getting enough.
Both Wellness & Taste of the Wild are quality brands though, but I have to ask why are you feeding the "healthy weight" formula? Is she overweight? Generally healthy-weight versions just have more carbs. Personally when my dog needed to lose weight I just cut down on the quantity and increase the exercise.
Good luck, let us know what you end up going with
Lady (1.5 year old tricolour) & Gracie (4 year old blenheim)
"Happiness is a warm puppy" - Charles M. Schulz