Since you have an iPhone you're kind of in a pickle, depending on what handset hardware you have and what OS it is running. As I said the iPhone 6 handsets and iOS8 generally have had cross-platform bluetooth issues as noted elsewhere online (in-car entertainment head units etc.) and ofc E1K (notifications of calls/texts/emails, uploading rides etc). Some folks with iPhone 5 and iOS7 are saying E1K pairs and works fine. Rumor has it iOS8.1 might fix those cross-platform issues, although who knows what ripple effects it might have with E1K. There seems to be a huge Venn-diagram overlap between E1K owners and iPhone owners, so there's a large sample size to deduce common issues from...the Cyclo isn't that common to even start with. There's several active iPhone threads right now of users venting on the Garmin E1K board.
You say you want navigation more than training features...do you have plans to want to use the device internationally? Magellan has been promising changing mapsets for months in a future update...and it looking like Magellan/Mio may have a hardware refresh out (Say a Cyclo "515") before that firmware ability happens on the 505. As I noted above, whatever mapset you buy with the Cyclo, you're stuck with for the visible future. So you take your USA Cyclo to Europe for holiday and you are SOL for navigation. Rumor has it, loading non-default mapsets on the MCyclo may cost money if/when it comes. The OSM is quite good on both Edge 1000 and Cyclo, the USA OSM is actually more complete than USA City Navigator 2015.20 in terms of bike paths/MUTs at least in my area. I don't ride routes/courses that much (maybe 5 times a year), so I personally cannot give an informed compare/contrast on that topic myself.
Battery life, the Cyclo wins by a bit. E1K can push 6 hours and change IRL maybe more, the 15 hour rating is utter fantasy. Both devices to save power and get anything close to rated advertised life-you need to start turning major things off. Screen lock (turning off the touchscreen input) on E1K will say 7-10% per hour of battery life. For longer rides, you'll need to bring a USB battery. Without disabling things I burn about 1/3 of my E1K battery in two hours (touchscreen on, BT paired and on, GSC10 and HRM sensor paired, GPS on, GLONASS off,smart recording, occasional segments).
The main things that drove me from wanting the Cylo were the fairly abysmal storage capacity (also note a typical 60km ride would generate 5megabyte of file logs). Also it was recently found that the wifi auto upload on Cyclo would autopost your rides publically on a 3rd party site (called "routeyou") without your expressed consent and without any start/end anonymization (a la Strava). When called out on it, support said RTF-EULA.
As far as the digitizers themselves...the screen on the E1K as of firmware 2.50 is pretty darn good tends to just work. I had the Cyclo only during firmware 4.0 and found the touch input somewhat fussy in reading swipe gestures which can be frustrating while riding. In darkness (night etc.), the E1K has a better screen IMHO as it has lower backlight levels and a low contrast mode for night riding (gray-black screen background with white characters) whereas the Cyclo has a higher brightness floor and no lower contrast mode as of firmware 4.0...ofc E1K also has auto-brightness adjustment so at dusk/dawn it will change contrast and also change brightness on the fly.
The OS firmware itself...the Magellan OS is pretty darn well streamlined and Garmin could learn a few things. Also the screenlock/unlock on the Magellan is easier to do on handlebars when riding than the Garmin.
This is the unofficial user-made support forums for Cyclo, since Magellan doesn't even have one:
CycloGPS Forums ? View forum - Cyclo 500 & Cyclo 505
The admin there is also a BF poster. He owns both E1K as well as Cyclo.