The configuration is obvious. We choose the audio system, possibly the MIDI channel for keyboard input, possibly a drum kit ... When using JACK, hydrogen connects automatically at startup.
The online help is clear. She has little use for the absolute beginner (the only potentially confusing is the choice between playing a whole song a drum pattern only).
I hydrogenating function on different machines, ranging from P3 600 MHz to 3 GHz P4 with 192 M RAM 1024 MB, and everything works perfectly. Directly involved, even without real-time kernel (computer music indispensable, especially for live), no perceptible latency ...
There is no stability problem, except sometimes at the opening of files with versions made too different from those used.
I use Hydrogen for a year. I greatly appreciate the free drumkits (with demos successful) provided - there is also a set of 350 drumkits to U.S. $ 29 that I have not tried - the intuitive general use, the ability to humanize running fine ... I find it unfortunate that there is not a stamped version 1.0, which show that the software is no longer experimental. But as it is more than sufficient to my happiness.
I never tried other drum machines, neither real nor virtual. In any case, Hydrogen does not sound like a robot base 80 years, and she fits perfectly into a set computer music Linux.
As this is a free software, the price / quality ratio is not applicable. I do not know any other free virtual drum machine, under any system. This software is unique and is one of the leading open source software, all fields.