I have two budgies. My first budgie (B.B.) would only eat seeds. He was lethargic and pitiful. I got a second budgie (Buddy) who was hand raised on pellets.
Well B.B. learned from Buddy to eat pellets. Once B.B. started eating Harrison's high potency bird food there was a remarkable change in him. He is like a new/different bird. He's very active and alert. (Quite chirpy too)
The difference is definitely the food and not having a companion because I had Buddy for several months before B.B. finally started eating the pellets.
I recommend feeding Harrison bird food to your pet bird. Be persist to get them changed from seeds to pellets. It is worth it.

Came on time, as described.

My disclaimer is that I have no idea if this works.
I started my birds on this because one is kind of obese and another was injured, so I wanted to make sure they were getting everything they needed in their diet. I add the requisite amount to their food, but I was unable to completely wean my birds off their regular diet. I keep the food in the fridge (as it asks).
That being said, my birds seem healthy. The obese bird is still obese, but we suspect an underlying problem like a fatty tumor (which this diet wouldn't cure). The injured bird healed up fine, but she may have done that anyways. Otherwise, I haven't seen any negative health changes. They are still lively and their plumage is bright.

I am still planning on using supplements to aid their overall health, but I'll most likely be looking for something cheaper next time.

When I got my baby English budgie from a breeder, I was told not to feed him a pellet diet, but after doing a LOT of research on the subject and going to a lot of avian sites, I came to the conclusion I wanted to do a combination of a high-quality seed, the Harrison's High potency super fine pellets and, of course, add organic fruits and vegetables for my little Sydney. I got Sydney when he was 8 weeks old and he is almost 12 weeks now and thriving! He likes the combination of seeds and pellets and then I also add a really high quality small parrot treat for him with pumpkin seeds and small peanuts and things like that. He kind of shreds the peanuts for fun and loves the bigger, fun things that small parrots eat. He's happy and he's healthy. The Harrison's company is stellar in their quality control and in their customer service. Any question you might have they will answer you honestly and professionally.

With eight birds, this is spendy food. I had bought it once for my birds, some of whom liked it more than others, and then had returned to feeding seed and veggies. Recently, I became concerned about one of my canaries and found that he had a condition that could be exacerbated by poor nutrition. I bought the Harrison's again and was delighted to find that all my birds are singing a lot more and are a lot more active now that they're on this food, so it's Harrison's from now on.

The pet store that we bought our parrotlet from/our vet recommended a different brand of pellets that were larger and fruity flavored. We had a lot of waste from them, and I saw these as highly reviewed and figured to give it a shot. It took our bird less than a week (pretty short) to adjust from his old pellets to these new ones. Now he loves them, as they are practically a treat for him after his breakfast. They are the bulk of his diet and the vet says he seems healthy and happy.