is the groove DJ a complete arranger with a sampler?
Yes and No.
Out of the box you have your Media Players for audio and video, VSTi's, Giga File, and much more....
However, if you want it to be an arranger you need to buy a licence for Live Arranger and then it will act like an arranger too. You also have to supply your own styles. Be it downloaded off the net or so on...
but the Liontracs website is far from informative...no online manuals
They are there. http://www.lionstracs.com/download/GROOVEX6OS4.pdf
any alternatives to the Groove DJ from other companies?
There's nothing like what Lionstracs are doing. Open Lab$ make PC's in keyboard cases. Lionstracs take the concept much further. Sort of like, you get all the benefits of the PC, but none of the headaches as Lionstracs OS sits on top of the PC OS and makes everything feel integrated.