I just had to talk about this since I did receive guidance about who to purchase here on the Wiki. Ever since I bought Karma and Sona, I learned a lot more about the game than I did before I got them.
Let me start by talking about Sona. Even before the sustain nerfs, I didn't think she was good. I used up way too much mana during the laning phase and had issues with it because I lacked the gold for a Philo stone and Tear of the Goddess (once I realized that I needed my partner to get the last hits because I was the support, not the carry). After the nerfs, I suddenly found some hidden potential in Sona. Did you know that I got to be in a team with 4 supports (including me as Sona) and a jungler? Suprisingly, we won! I laned with a Janna (we both took Heal and Clarity for summoners so it was very hard for the enemy to harass us enough despite the fact that they were Cassiopeia and Orianna!). Soraka took mid against Caitlyn, Taric took the solo lane against Garen, and Warwick and the enemy Master Yi proceeded into the jungle.
The laning phase wasn't too good for the other two lanes, but fortunately, Ww's ganks were very successful. Taric and Soraka ended up pushing their lanes to the towers, while Janna and I destroyed the tower in our lane. Our main highlight was from our teamfights and pushes. With three "squishies" on our team, it was hard for the enemy to focus a single target. Taric, Soraka and I kept spamming heals so it was hard for the enemy to scare us off, let alone kill us. For the first time, I wasn't afraid to jump into the front lines as Sona, and it felt exhilarating... and hilarious. xD I'll never forget this match. It was originally going to be just me and Janna as the supports, so seeing two other players participate made it even more interesting! All the enemy team did was laugh, and I don't blame them. But I think they underestimated us.
But enough about Sona. Now I want to talk about Karma. It took me a few weeks to realize that Karma should not be played as a support when her damage has so much potential! Heavenly Wave + Mantra Soul Shield + Spirit Bond allowed me to clear minion waves in a matter of seconds, so pushing was not a problem. Karma also had mana problems, but I ended up rushing a Catalyst to deal with that. When I realized that Karma wasn't squishy, I definitely took advantage of that quality! Enemies focused me a lot, yet I didn't go down. Some even proceeded to tower dive me... Big mistake. I was stuck at my tower going 1v4. I don't remember exactly who dove me first, but I remember that I ended up getting two kills and scaring the other two away. Some say Karma is OP, while others say she's UP. Personally, she should be viewed upon the way her concept intended her to be: balanced (though I still sort of see her as OP xD). From then on, I went AP Karma rather than Support Karma.
I love my supports, even if they aren't pure supports. I just hope they don't become extinct. The sustain nerfs had me worried at first, but I still think that there are plenty of support players out there. Thank you to everyone who helped me with the Karma vs Sona debate I had a while back!