I should qualify this review by mentioning that I was on the Beta team for Black Magic and, for this reason, my 5 ratings in 'value for money' and 'documentation' categories should be taken as neutral.
Loop creation with BM is very quick and easy to grasp and with the randomization features you can generate a huge variety of loops with zero effort. The randomization itself can be as specfic (just one sequence for example) or as global (essentially generating a whole new loop) as the user wishes.. Maybe you like everything except the bongo that is coming every quarter note.. you can randomize just that sample until you find something you like better or randomize the bongo's sequence until it fits into the groove a little better or just throw a little delay on the bongo..multiply this by 10 (each sequence\sample is its own "module") and then again by the sheer number of tweakable paramters and effects and it becomes apparent that the possibilities are literally infinite. Conversely, if you want to completely construct your loop from scratch with control over every step, this kind of control is available too. Once you find that perfect groove, it's time to capture it. Since the loops are recorded by the VST itself, there is no setup (ie rendering or using an audio capture vst) other than specifying the length and bit rate; BM automatically records the entire loop from the beginning of the sequence for a perfect loop every time. No need to search for the loop afterwards: you can play it back from inside the vst and there is a button which opens up the folder where the loop was stored (with unique name\timestamp and organized by tempo!) and I've just been dragging the wavs from that window into the DAW timeline or even right into other vsts (in my case Linplug's RMV) and messing further with them there (slicing etc). You can also engage the record function in a manual way with the B5 key while the loop is playing. You can have live control of each of the 10 sequences.. you can play each sample as a one shot (in the C2-A#2 range), or hold a key down to trigger and loop the sequences until release(C3-B3 with B3 being all 10 on at once).. this mode can also be set to "sticky" so the keys toggle on and off with each press. Sticky mode is a dream if you like to build up a groove gradually by bringing different elements in and out with the additional perk of being able to throw in a roll or polyrhythm by hand on the lower octave. If you play keys higher up the keyboard you can manipulate the pitch (or res\cutoff among other things) while the loop is playing for a lot of interesting variations. In addition to hundreds of percussive samples included (in the full version) there are some 'instrumental' samples which respond to this pitch manipulation rather well (although there is also something to be said for playing a melody with a snare drum). You can use your own wav files with the full version to add even more expandability. All of the above can also be recorded as midi performance data for further tweaking later. So whether jamming live or creating loops, the midi control aspect is integral to the experience. Andy at HG Sounds is a top-notch guy and his response to suggestions and critiques during the beta-phase was quick and effective. I can safely say this is even more apparent in his relationship with his customers (which I also am). There are some issues with sluggish knobs and rendering in Tracktion 3 but these have been mentioned prominently in the information pages of the website and do not affect the stability in any way. It worked fine for me in Reaper and Minihost. I personally don't think it would be the best choice for those looking to make realistic acoustic drum loops but would be very useful for any electronic genre. It lacks midi output (afaik) and doesn't load audio loops, so it is kind of sitting right in the niche between the other percussion\drum products I've used, while not actually replacing any of them. The GUI can at first be a little daunting and the hardware emulation esthetic makes for a bit of flipping around but once you realize where things are, the why becomes more apparent. Swapping kits and samples is easy and quick, the mixer page allows fine control over important parameters for each of the 10 samples, and the seqeuncer page has a step-sequncer grid for each of the 10 sample modules with many options for tempo, length, soloing etc. Black Magic is a really unique approach to rhythm and while it may share some characteristics with other "drum" vsts, I can't think of one that really does what it does. It is awesome for creating mountains of loops to feed into other apps (for slicing etc) while at the same time functioning as a highly controllable live drum machine\groovebox. Highly recommended!