Bethesda games are poorly made from the RPG standpoint, but are complemented well by their free choice and free world mechanics.
Bioware games are generally really well designed, but have this huge problem in that you feel complete with the game 2/3rds of the way through. also, ever since it was aquired by EA their games have been seing a steady decline as the respective IP's are milked for every dollar they are worth; For every Dragon Age and Mass Effect which are absolutely great from the RPG standpoint, you have a Mass effect 2 and Dragon Age 2 which absolutely destroy the RPG mechanics for 'better flow'
Square Enix is really the only choice considering they not only have some of the Best RPG titles i've seen, but also that they continually push the bar with their development. And while some of their progress has been in the wrong way and lead to horrible game (cough*Final Fantasy XIII*cough) it is still some sort of progress.