Yes, it is surprisingly polished. I tried playing the first three Phantasy Star games, but each time was put off by one annoying design flaw or another (such as the camera not being centred in II, so that you can't see very far ahead when exploring). In the fourth game, everything just works.

Just about the only annoying flaw still left is that it's not obvious what items do, and you kinda will need to memorize lots of random names... (Well, or have a reference near you while you play) This is actually mentioned in the interview as them not wanting to be too explicit about what things do (not saying "attack +20" etc.) - unfortunately, it's one of those design decisions that does create friction for the player.

PS3 was one of my favorite games, maybe it's time to get myself one of those pocket emulators and play PS4 finally.

Not sure if it was on PS (except as part of the Sega Collection disc), but I played it on the Sega Genesis. Loved it.