It's more powerful because the hard-coded limit of 17 connections per
download in the regular version and 20 (25?) in Pro is set at 50 in the beta
test version, and only in the beta can you force the host module into
ultrapeer mode. These "test" features were never intended for the public.

More importantly, 5.1.0b25 came out before the remote controlled download
throttle was secretly added to the code. At any moment they could cut your
download speed to any level they choose, right down to zero. Some users
have also reported that 5.2 versions fail to download from LimeWire sources
and switching to b25 fixes that annoyance.

Of course, as expected, the new owners have severely crippled the latest
version 6 so that it only lets you find and download music and videos of 15
minutes or less in length. That means you can't get anything else at all.
Such arrogance could only come from the MAFIAA.

Search results vary widely from moment to moment but both Pro and the test
versions were set to perform better than the normal and Lite versions in any
case. If there's a difference between the two it is small enough to be
completely irrelevant. You still find what you're looking for and the rest of the
sources are automatically found during the download.

You cannot stop the upgrade process anymore either. They force the
download on you and then that annoying reminder to install it never goes
away. You could delete the new installer but then it would just download
again. What you can do is switch to b25 because there are no more
updates for that series. That means no back-door download against your will
and no nag.