I've been to Sunflower a handful of times and it's a quality grocery store. Fresh produce, fantastic selection, reasonable prices, friendly staff, and not so big that it's overwhelming to shop here. Like Sarah K said in her review, "It's like a budget Whole Foods."
I ran in today to get some last minute ingredients for Rosh Hashonah dinner, and I was in and out pretty quickly. They don't have the best selection when it comes to muffin mixes, so I had to go to Safeway for that, but other than that, Sunflower rocks! Their bulk food section particularly is impressive... and the prices are fabulous! (I think AJ's charges at least double what Sunflower does on certain items).
When I live in Old Town (hopefully moving in the next 2 weeks or so), I will make Sunflower a regular grocery shopping destination for sure.