Keep in mind that regardless of the tool you choose you will need to setup each device and register it on iTunes Connect. Note also that there are limits:

* 100 users/devices per Developer Apple ID (Apple seems to me migrating to a 200 devices limit)
* Devices can be removed/replaced just once each membership year
* A time limit of 90 days

There are some alternatives:

* Ad-hoc installation (needs physical access to the device)
* Testflight (https://testflightapp.com/) the one I use and recommend +++
* Pieceable (https://www.pieceable.com/) lets you test over the web browser
* AppHance (http://www.utest.com/apphance) is a TestFlight like service
* HockeyKit (https://github.com/TheRealKerni/HockeyKit) is an opensource stack to host beta apps on the web (still needs the device registration on iTunes Connect)
* HockeyApp (http://hockeyapp.net/features/) an TestFlight like service