From what I understood, Ichigo's oryginal power was initially one, but quickly separated into two: Zanpakuto (made from Shinigami-Hollow powers) and Quincy part. Izach (Inner Zangetsu Bach, since now he is officially "Zangetsu"), being far more mature than Ichigo's other parts of power, have easily taken total control of Ichigo's Zanpakutou, but in time, Ichigo's other powers slowly matured and started seeping out. Then, came Rukia, which lent her own power to Ichigo, which allowed a part of Ichigo's Zanpakutou to come out, thus Ichigo became a Shinigami. After this, Ichigo lost the power that Rukia lent him and Izach again gained total control over his Zanpakutou, but thanks to Urahara's training (which forced Ichigo to awaken his Hollow part of Zanpakutou), forced Izach to give out a part of Ichigo's Zanpakutou, since otherwise Kurosaki would have died (at this point, Ichigo's Zanpakutou was split in two, the Hollow part and the Shinigami part that was still kept by Izach). That is why all this time, Ichigo was using only the Hollow part of his Zanpakutou, since Izach was blocking the Shinigami part of his Zanpakutou (of course at some points Izach lent his own power to Ichigo, like against Kenpachi or the first fight against Renji and other moments when Ichigo's eyes were burning with blue fire).
All this time Ichigo was using Hichigo's power, that is why Hichigo had to be the one that taught Ichigo how to use Zangetsu (it seems that Izach couldn't do it, because he had no clue how to use it himself), even at the Bankai training, Izach was simply his opponent, but it was Ichigo himself that had to learn how to intentionally draw out the power from Hichigo (in this case learn how to use freely GT, which was the actual requirement to obtaining Bankai). That is also why Hichigo was more prone to appear when Ichigo was using Bankai (especially Kuro Getsuga), because at those times Ichigo was using more of Hichigo's power.
After the Dangai training, seemingly for the first time, Ichigo took his real sword (not quite, since the sword was still partially in Izach's hands, but Izach was lending the power of the sword through himself) into his own hands, a sword which proved to be so powerful that it easily cut down mountains.
At the current arc, Izach finally let go of his part of Zanpakutou that he held all this time and was ready to fade away (or simply get out of his way), but Ichigo didn't like that and reincorporated Izach into that part, which resulted in Izach becoming a true Zangetsu, the same way as Hichigo was a true Zangetsu, thus Ichigo's sword became Shinigami-Quincy and Shinigami-Hollow, or so it seems .
This probably means that Ichigo have quite likely gained superior powers of what he held before, plus new ones. It's even possible that a third part of Zanpakutou was born representing the Hollow-Quincy part, which probably would result in a black mask, that after putting on would give Ichigo burning blue eyes (that is reasonable since the Hollow Mask was actually shown among Ichigo's Zanpakutou techniques that he had drawn forcefully, when Ishin was mentioning them to Ichigo).
@Paul, from what I can tell, Ichigo has a long coat, similar to Fusion Zangetsu, then he has a black poncho-kind of thing, that is around his neck and goes down, covering half of his inner-coat from the side, then he has that scarf-pattern-thing that goes from his head, again over his shoulders and then hangs down from his side, and then there is a black belt over them, finally, he has gloves and an overcoat over this.