Previously, I have tried Wolf Camera. They have excellent turn-around time of course (less than an hour) but I have prints I made from them less than eight months ago, and the colors already look a bit off.
CafePress.com does poster prints, but I've found their print quality to be very hit-or-miss, often over-saturated with colors. (Their t-shirts are fine, but results on their calendars, notebooks and tiles have been spotty.)
ImageKind.com provides really nice quality prints, but I'm not sure what their long-term durability is.
There's so many print services these days, ranging from Flickr affiliates to Snapfish.com (not really happy with Snapfish quality) and so on... it doesn't have to be flashy, it just has to be quality without crazy prices.
Has anybody used Imagers.com? Or is there any other company you'd recommend? (I also appreciate any business suggestions in Chicago, as that's local and doesn't have to be online, just have digital price capacity for me to be able to use).