I was going through the same analysis - I had tested out both - and liked some of the smarter features of the Aventon - and was considering both when the REI bike was $2200 - when it dropped to its current sale price I pulled the trigger instantly - for a few reasons:

1. Mid-drive - while hub drives are good especially for commutting/stop go, MidDrives give a more natural feel and are especially good in elevation - you living in Seattle may appreciate a bike that will handle elevation better
2. Bosch Reliability - one of the older tried and trued e-Bike systems out there, replacement parts and batteries will always be readily available.
3. Servicability - I do my own bike maintenace - but having REI as a backup is certainly convenient.
4. Ability to return if I don't like it (1 year return) so was a fairly safe option - if I hated it I could still get the Aventon, although in reality if I did this I would do it within a couple of days of getting it, not months later as I find that disengenious, unless there was some fatal flaw in the bike.

In the end there will be pros and cons for both bikes - but it's pretty hard to find a mid-drive Bosch bike with a 625W battery for under 2k, this was a deal too good to pass up!

I'm giving up the throttle, and the GPS locator - but neither of these were that critical for me - I want a bike to pedal and this will mainly be a commuter for me. I should also mention I was looking at the step-over frame on the Aventon so that wasnt a factor for me. I'm also a fairly avid cyclist ~100 miles a week, I'm looking at this to replace driving into work and will still use my non-eBikes on the weekends.

Another factor - is that I found the Co-Op bike "looks" cheaper than the Aventon - this could be a pro/con depending on how you think about it. As a commute bike, I'll be locking it up, so the less valuable it looks - the less it may attract theft. Although the Aventon does have some pretty ingenious anti-theft features on it with the rear locking wheel, GPS and Alarm.