I used a seedy three for about a year, and was mostly pleased with it. Very comfortable, and roomier than you might expect. It made it through a number of downpours without anything inside getting wet. It seems pretty well built.

I did have a few issues with it, though. First, there are very few pockets...only three thin internal ones. Second, it's not technically waterproof. While I had no problems in rain, when my back got really sweaty it would seep through the bag and whatever was resting against my back would get damp. However, I should note that I sweat easily, and a lot, so that may not be an issue for you. Finally, after seeing the split-strap design on other bags (Chrome, Baileyworks), I started to get annoyed with the single-strap, over-the-head design. I don't know if any of these are issues with the complete seed.

Anyway, since I've started using my bike as my primary means of transportation, I've found myself wanting to carry more stuff than when I originally bought the bag. I've since picked up a Baileyworks SuperPro that I'm quite happy with.