I've had recent experience with both of these routers.
What they both support:
- dual band
- GigE ports
- IPv6
- Guest Network (2.4GHz Band)
These are some of the differences I've come across that may be useful.
Either should work fine in small apartment.
TP-Link TL-WDR-3600
Pros
- Removable external antennas
- Supported by third party firmware dd-wrt, OpenWRT + Gargoyle Web UI
- 2 x USB ports so it can act as a print server and/or file server
- Physcial on/off switch for Wireless on rear of device
- Has an online emulator so you can see what the web interface looks like before you purchase: http://www.tp-link.com/ca/support/emulators/?model=TL-WDR3600
Cons
- User interface is pretty plain Jane. The third party firmwares look as good or even better
- Bigger desk footprint
- Web UI is very granular (pro/con?)
- Crap tonne of status lights on the front that I couldn't find a way to turn off(pro/con?)
Cisco (Now Belkin) Linksys EA2700
Pros
- User interface is very slick and it's very easy to set up things like Access restrictions for time of day and sites
- Linksys Smart Wifi "Application Enabled" so you can configure/monitor it from the cloud and control it with an Android/iOS app
- You can turn off the port lights which is handy if the router will live in a bedroom
- Looks non-descript sitting on a desk and has a small footprint; passes the wife test

- Can pick it up a refurb for as little as $20
Cons
- Cloud enabled
- No usb ports
- Internal anntennas
- No third party firmware support currently and may never have.
That having been said, my home network has 2 x EA2700 for a couple reasons: I am a cheap bastage and I got them both as factory refurbished units for $40 (2 x $20) on sale and the parental control features work well in conjunction with the Android app. One is configured as a router and the other a wireless bridge.
I'm not stoked about the 5GHz coverage but I did not list it as a con aqs that probably has more to do with my smartphone's wireless performance on 5GHz which is admittedly pathetic and was just as poor with the WDR3600 and an Asus access point (i.e. standing next to the device, the 2.4GHz has a much stronger signal on my phone than the 5GHz)
The cheapest I could find the WDR3600 was for $50 + shipping. I did buy one however for a friends SOHO network where the USB ports were a useful feature. Also I installed Gargoyle on it right away as we wanted to set up some white listing of sites (in retrospect, we could/should have used OpenDNS and will probably go that route for simplicity).
For my home network, I would rather have the WDR3600 with the USB ports as I could then ditch an old PC that mostly operates as a print server.
Any questions, let me know.