Okay, I've decided to post a post describing my thoughts on each summer canister set, including why I like and dislike each of them. I will try to be fair and find as much good and bad for each set as possible...
I'll start this off with everyone but me's favourite canister set: Mata NUI!!11!!!1!
Okay, here goes:
Why I like him:
-Its Mata Nui
-New Ignika in helmet form
-The shield/upper arm armour piece is cool, and it comes in two different colours
-ankle armour!
-Not much silver
-Ice blue(like on Strakk) head piece
Why I dislike him:
-Too much Keetorange
-Legs are shorter than arms
-Thin waist
-Mask Blends in with torso armour too much
-Not much silver(yes, a pro and con. I think he'd look better with a bit more silver, kinda like Toa Ignika)
Okay, I did't put: No Gold as a con because we wouldn't complain about not getting a gold canister anyways, and we only complain cause its Mata Nui. So there, I complained about him a lot(and I still don't like him), but I found one more pro than con. I really tried to look at Mata Nui with the Glass Half full perspective

Aaaaaaaand moving right along up the ladder to the top: Gelu! (yay!)
Why I like him:
-White and dark blue go nicely together
-Many ice-like pieces (and a reason not to get Metus

)
-Really well done mask
-His weapon is very kewl
-Ice blue head piece
-He just looks like a very well done set
Why I dislike him:
-He may be kinda short...
Can't find much to dislike about him. He's a great set, and mostly flawless. Definately a must have.
Vastus
Why I like him:
-Great upper arm armour
-Really well done mask
-The scythe is cool, as is the way he holds his weapon and thornax launcher as a staff
-Good colour scheme
-New upper arm pieces
-New use of inika thigh armour
Why I dislike him:
-The legs, well, I'll let Omi comment on them...
-New use of Inika thigh armour(once again, a pro and a con(just wait until Kiina...))
-Very 'bare' look to him overall
-A staff reduces possibility(as seen on six 03 sets...)
Overall, Vastus is balanced between good and bad. I very much like him though, and find that his upper body is very well designed, while his lower body(legs) need work. The Inika thigh armour thingy, well, its innovative(kinda), but he has a lack of armour because of it...
Kiina
Why I like her:
-...uhhh, custom torso...
-Nice mask DESIGN
-New upper arm/leg piece
-Good upper arm/leg armour
Why I dislike her:
-overall the set is terrible(sorry, that came out a bit harsh...)
-The mask does not match the set at all in the pictures I've seen
-Same arm and leg design
-The custom torso is bad from the looks of it
-open ball joint CLEARLY visible
-The colour scheme is not shouting it that its excellent, its crying cause (insert Omi quote here)
Okay, I really dislike this set. I have no comment for the weapon because I have yet to see a good picture of it. On the canister it looks nice, but then, so did Krika. I don't know what was going on when the designers picked the mask colour, but it was not a good choice...
Ackar
Why I like him:
-Mata red and orange
-Flame piece is very cool and fire-esque
-The hilt for the sword is cool
-A wide variety of recoloured pieces
-Ankle armour
Why I dislike him:
-Very few new pieces
-Hand colour
-The helmet looks small(and it belongs to Berix)
I like this set, but the amount of new pieces is somewhat low. Its a good set, but I'm not sure I'll get it.
Stronius
Why I like him:
-Club
-New armour piece?
-Mask is cool
-Colour scheme is very good
Why I dislike him:
-Short...
-club is not Bionicle-ish
I haven't got a good look at Stronius, so I can't comment too much. What I have seen so far is good, but I can't say too much about him yet.
And that about sums it up. This is based purely on toyfair pics and some other comments already. Fell free to agree or disagree with me.
-ZLS