If you are looking for Information about PSU Clementine, Go check their Wiki
Manufacturers
There are four diffrent Manufacturers for most items within PSU, that have their own properties on what effects the items.
GRM - Main shop located in Parum Normal ATT and PP on Weapons, Equal stats on Armor, Weapons and Armor named normally (Brand, Megaline). These items are recommended for those who like to have equal stats, however, they have no real outstanding strenghts.
Tenora Works - Main shop located in Moatoob High ATT but low PP on weapons, High Def but low Ment. Weapons and Armor are named oddly. (Al Daga). These items are recommended for Hunters, as they can deal out massive damage, but since the PP is lower, you won't be able to do Photon Arts as much as GRM or Yohmei Corp.
Yohmei Corp - Main shop located in Neudaiz High PP but low ATT on weapons, High Ment but low Def. Weapons and armor have added letters. (Ryo Sabra). These items have a huge stock pile of PP, making these items great for Force's and Rangers, but, as the ATT is lower, you might not do as much damage as GRM or Tenora Works.
Kubara Kubara products are alot diffrent than other companys products, as Kubara products can only be synthed and they're useally rare items. (Fluorescent Bulb) These items are very strange, as they start off extremely weak, however, once they've been grinded, they gain huge ATT and PP. The only downside to this is that the item's are rare, and synths often fail, and the fact you need to grind it for it to gain power, you need to be careful.