Xiaomi WiFi 3G runs on MT7621, great design of case, but non-trivial to re-flash with openwrt.
UBT Edgerouter and ZBT WG3526 use MT7621, too.
For personal use, or small quantity, the Xiaomi is the device of my choice.
Linksys tries to hide the hardware revision from the buyer as much as possible, it is marked on the back of the device (model/ FCC ID) - if you're lucky also on the lower of the three barcodes on the small lower edge of the packaging (but this is not always there).
As for the EA6350v3, the only reliable way of identifying it is the read the model number on the bottom of the unit itself. Unfortunately there's no way that I know of to determine revision on the box itself.
It is better in terms of performance however you might only be able to run one radio at a time due to RAM limitations.
Thank you all for your input, much appreciated.
Very interesting discussion.
My current internet is only 8/8 Mbit (It may reach double or triple that in the near future).
But I also want to use an ftp server and a vpn server with the router.
I have an EA7300 that fell on my desk yesterday I found this post looking for more info. I have not built a router firmware from scratch before but I'm willing to give it a shot if someone can hold my hand a little. I have some Linux experience and have used OpenWRT for many years (at least through Luci). If I can get one to a dev without costing me an arm and a leg I would be happy to let them borrow it to further the cause.