BrickDreamer

Toa Mata, as they're more iconic, and being the very first wave, less people would have gotten them because it was an unknown theme at the time. Age also has its advantages, as newer fans would want to get the original six.

Toa Nuva, 2002. Remember that in 2008, even though they got the adaptive armour, they lost access to their suvas and five extra kanohi nuva powers. When they were sticking close enough to one another to share the powers, that wouldn't matter, but the team does split up an awful lot. And at those times when a toa works alone, five extra superpowers count for a lot.

 

Next would be the 2008 Nuva, for reasons already discussed.

 

Next in power would be the Toa Hagah. They were picked as the best of the best, heroes who had proved themselves across the universe and had thousands of years of experience. The Nuva may have had more power and control, but the Hagah have been pushing the limits of their abilities in many different situations for a long, long time. Their masks powers are pretty useful as well, from emulation, getting power to match whatever an opponent can throw at them to teleportation, growth for huge power and rahi control, because rahi can be found just about everywhere and have some really awesome abilities. And then on top of that even, they each had a rhotuka power as well, just adding another string to their already impressive bows.

 

Next would be a close call, but I'm going to say the Mahri over the Inika. The Inika had their powers intertwined with lightning, but that wouldn't always be a good thing. The difference comes in that extra little bit of experience, and in their mask powers. The Mahri powers are, in my opinion, a bit more powerful and applicable in a greater variety of situations. In particular, Hahli's masks, the elda, great mask of headaches, versus the faxon, mask of kindred. Again, rahi have an incredible range of abilities, from breathing fire and sonic blasts to camouflage, intangibility, accuracy, enhanced senses and many more. Then there's gravity, stealth, reanimation (Zombie armies anyone? Yes please!).

 

Next would be the Mata, just edging out the Metru. Then come the hordika, whose elemental powers were restricted to rhotuka and whose masks were inaccessible. Next to last we have the stars heroes, as there were only three of them and Gresh lacked a kanohi power, and finally, the glatorian. During thieir year, they had no elemental or mask powers, fighting only with their strength and speed. Even with that, though, none of them could beat a skrall one-on-one. Once gresh got elemental powers, he was able to blow away dozens of them at once, so the team without powers (or when only a few of them eventually got powers), they are obviously much less powerful than any fully-superpowered team.

In terms of sheer power, yes, I agree the  Toa Nuva are more powerful, but in a fight, they could easily be defeated by stealing their Nuva symbols like the Bohrok-Kal did, so I would give it to the Toa Hagah.