I bought a Droid Maxx from the states and is using it on Fido right now. Works alright, ocassionally 4G signal, HSPA+ most of the time. One thing is that it gets only 3 bars max most of the time for some reason (Waterloo, Ontario). But not major enough to keep me form using the phone
Although this thread is quite old, I'd like to add a little update since I came across it .
Things to Know
Your device must be compatible with the Fido network, which uses GSM, UMTS, HSPA and HSPA+ at 850 MHz and 1900 MHz.
To access LTE network, the phone must be compatible with:
700 MHz on Band 17;
1700/2100 MHz on Band 4;
2600 MHz on Band 7.
Hope this helps!