I would like to share my experience with the Feit T8 LED fixture and offer a brief comparison to the Utilitech T8 fixture I purchased from Lowes.
After seeing this thread and coming across the lights in Costco, temptation got the better of me and I purchased one to replace an old T12 fixture in my garage that was on it's last leg. It took me more time to navigate past all my wife's classroom boxes and supplies to be able to get under the old fixture than it did for me to unbox and install the new LED fixture! Initial impressions were that it wasn't the greatest construction, but compared to what I would have to pay Cree or perhaps Titan LED for a fixture it seemed appropriate for the price. The unit weighs next to nothing and can either be mounted on the ceiling or suspended with the provided link. Seeing as my old fixture was suspended by chains, I utilized the existing hooks. As soon as I stepped down and turned on the light, I was amazed at what I saw. The light was very bright, natural almost, and had great coverage. I was very pleased with my purchase.
My issue comes down to my detached workshop. It is approximately 26'x28' with 9' ceilings, all plywood painted white, with six rows of five 4ft 2 lamp F40T12 fixtures with most only having one working side. I liked the Costco fixture but not sure I want to spend the money on 16 fixtures for the shop. So, I stopped at Lowes and picked up the 4ft 2 lamp Utilitech T8 fixture with two GE 4100k 2900 lumen T8 bulbs. I replaced the LED fixture in the garage with the T8 fixture so I could have a more direct comparison. I will add, I like the construction of the Utilitech fixture more (granted it's an $18 fixture...). My wife helped me with a before and after, and we both reached the same conclusion: The Feit T8 LED fixture was brighter and had better coverage, but not by a large amount. I made sure they were both suspended the same amount, both 4100k, but for our eyes we liked the LED lighting more.
I used the LightMeter by whitegoods app on my iPhone 4s as method to compare the output between the two fixtures. No, I do not own any calibrated light meters nor do I have access to one, this was not intended for any scientific comparison but to compare two numbers for my own curiosity... besides, the app is free so I got my money out of it! At approximately 6 feet directly under the fixtures, the LED fixture showed 55fc while the other fixture actually showed 70fc! Perhaps the other T8 fixture puts out more lumens, but I personally felt the LED fixture did a better job.
My plan is to replace my workshop lights in a 4x4 pattern with 12 of the Utilitech T8 fixtures, and put in 4 of the Feit LED fixtures on the back row over the workbench area. This way I feel like I would get the light output I prefer over the areas where I would be working closely, yet still provide plenty of light over the body of the shop where I have the cars setup.
You can't go wrong with the Costco lights, but if you cannot justify spending $40 for lights, the $18 Utilitech T8 fixtures at Lowes are a close runner up!