I'm usually an Instapaper user. I've used it the longest, and I appreciate that I can limit how many articles are stored on the iDevices; pocket has no such limit, and I find its database can grow wild if you don't read/delete/archive articles frequently (had it up to around 600MB without really even thinking about it). However, iMore.com and Instapaper have been troublesome for me for a while now. It just doesn't parse/download at least half the articles I save there. So Pocket has been better in terms of actually getting articles parsed/downloaded, but I prefer the look/feel/operation of Instapaper (if only because of familiarity).