Just wanted to give my opinions (both positive and negative) on each of the main 6 couples. Yes they are in order from my favorite to least favorite.

Tecna & Timmy

I actually really love this one. I think it is super cute. The fact that Timmy is the clumsy shy one and Tecna is not. Usually it the other way around--the female is the cute, shy, klutz and the male is the one to go "it's cool I still love you". I think it's a great twist for the roles to be switched. I also love the fact that they are 'the nerd' couple. Typically in shows like Winx the 'nerd' either gets the 'hot' boy or no one at all. It's really great to see a change in the stereotypes. Honestly I don't really even think I can name any cons of this relationship, it's sweet, genuine, and loving.

Layla & Nabu

I like this one simply because in the beginning Nabu was borderline stalker and Layla was pretty much "lol screw off Nabu...single and proud!" And then she gave the guy a chance and they had a really great relationship. And despite being single no longer, Layla stayed badarse and awesome. I also (this is gonna sound bad, but hear me out) liked how they killed Nabu off. It added a douse of reality to the show and gave Layla more depth. I was so sad to see the couple go, but dayum, that made for a shocking tragic love story. One I didn't expect to see on this show.

Musa & Riven

Musa and Riven...though I do like this couple, they actually did fall out of my top 5 do to the borderline abusive nature of it. No offense intended, but Riven no doubt has a bad attitude. He and Musa are constantly bickering--had this not been a kids show, we may or may not have seen punches thrown. And then there was the whole Darcy thing, but I'll give him a pass on that as it was a spell. But looking through all that, I think Riven can be sweet when he wants to be, and when they get along...well, they get along well.

Flora & Helia

I think this ship is cute. Which for me is good and bad. I'm not too big on cutesy and fluffy, especially when it's all sugar and rainbows. That's why I liked when Krystal came into play. Again, gave it a douse of reality, the possibility that a significant other can cheat on his lover. As it turns out he wasn't a cheater, which is definitely a good thing and Flora didn't go all b****y on him so I can appreciate that. I am also quite fond of the fact that in the 4kids dub the two met based on his artistic abilities. As a fan of art I think that was a neat way to bring them closer.

Stella & Brandon

I'm pretty iffy with this relationship. I liked it a lot more in seasons 1-3. In season 5 Stella kind of started to treat him like crap; he was like her personal mannequin and if he hesitated to tell her that her fashion line was amazing she would be all 'OMG you hate it don't you.' I did not like how she treated him like something off a chic, dress-up slave. However I liked their relationship in the previous seasons. She wasn't to clingy and he wasn't Mr. Prince Charming. It seemed like a pretty typical relationship between two teenagers. So over all I am in the middle with this one; don't hate it but I don't love it.

Bloom & Sky

Now this one is the one where I'm gonna give the heads up; I do not like this couple, most of this will consist of cons. If you don't want to hear it, don't even continue reading if you do, and you get offended, that's you're own fault. With that aside I will begin. My #1 reason for not liking this couple is the fact that Sky is an out right liar, cheater, and deceiver. He had a fiance, he was going to marry someone and he knew it. Yet he takes Bloom on multiple dates from episode one all the way until he is discovered. Heck, he even lied about his name so he could get away with it. He was leading both Bloom and Diaspro on and that's not okay under any circumstances. People argue that this course of actions is alright because it was an arranged marriage. By all means, I think that makes it worse. He knew his responsibilities as prince and he intentionally neglected them in changing his name to lie and lead two women on. And one of those women after finding the truth--didn't get mad--but helped him neglect his royal duties. He was supposed to marry Diaspro, even if he didn't love her, that was a law. In most situations like these doing something like this would be considered an act of treason and could result in punishments as far as executions...to both the man and the woman involved. Yet both Sky and Bloom get away Scott free and that annoys me. As for what Bloom did--after finding out about Diaspro, did she stop going after Sky? No, she attacked Diaspro. And when Diaspro fights back or tries to win back her man she's considered the villain by both the characters and the fandom. Thus earning my stamp of 'LOL NOPE!'
And then there's the sheer fact that the relationship is so Sueish. Typical prince charming, 'perfect', blonde haired blue eyed, hot boy with the 'perfect', beautiful, powerful girl. And there are hardly any struggles. He's the perfect guy who treats his girl exactly right. Sounds good. But really, it just makes the relationship seem unrealistic and boring. With the exception of the drama caused by Diaspro coming back (don't worry you can count on the plot to bring them back together every time) there is literally no trouble.
The only positive thing I have to say for this couple is the fact that at least Bloom is not a total wimp. She doesn't call him to save her every time she is in trouble. Just a few times. And I suppose that's good, the last thing the show needs is a helpless damsel in distress. So kudos to Bloom (for once) for not taking on that role and making the couple 100% dislikeable (in my opinion anyhow).

Anyhoo, thanks for reading, feel free to agree or disagree in the comments.