Hi Mario, I have not heard the ARC preamps but from what I read there are big differences between the various ARC preamps with the Reference series being better than the LS series and each generation of ARC preamps being a step up from its predecessor.
I think one difference to consider between ARC and PS Audio is that ARC uses the 6H30 tube, which gives the ARCs a transparent sound and has sharp transients, etc. Some describe it as a more solid state type of sound but still having some tube characteristics. The PS Audio can use a variety of tubes (12AU7, 6DJ8, 7DJ8, 6922, 7308) and probably has more of a traditional tube sound. Not as quick and clean as the ARCs but it is still a very nice preamp.
Your English is very good, by the way. Better than some of the Americans who post here.