I understand that the MR46 has internal antennas and the MR46E has external antennas, but what does that mean practically? Does it give better coverage? If so, how much better? What does "better" mean?
It does not give automatically "better" coverage, but "other" coverage. By the choice of the correct antenna, you can "direct the signal" to where you want to have it. A well sought of WLAN-requirement and solid WLAN design will tell you if you need them or if you can go with the less expensive models with internal antennas. If it is intended for an office environment, you will likely be fine with the internal antenna-devices.
@ChesterX @The actual difference you need to understand is the difference between the outdoor and indoor antennas. The major difference is signal strength of the antenna with some of the other features which may be not so important. All vendors have same difference most of times
@Inderdeep all of antennas for the MR46E are actually marketed as indoor antennas, even though they are not internal to the AP. Though it may or may not be possible to use them outside under a canopy... 😉