1. 10th Gen. All of them. ALL OF THEM
2. 8th Gen. Love two, kinda meh on one now.
3. 6th Gen
4. 7th Gen
5. 5th Gen
6. 9th Gen
7. 3rd Gen
8. 4th Gen
9. 2nd Gen
10. 1st gen.
A lot of people say that 9th Gen is the strongest Gen, but I'm going to have to politely disagree. I'd give it to either 6th gen or 10th gen.
9th gen has one really major talent, Riho. Zukki is funny and can sing, but she stays in the background too much. Eripon and Mizupon are really weak in my opinion. Mizupon is boring and, though she has a decent singing voice, she sings boring. I'm not sure what Eripon is going for. I love the fact that she loves Risa and all, but she's kind of all over the place for me. She can't sing really well either. I think I'd put Eripon as a grower now that I think about it.
If we looks at 6th gen, 3 out of 4 of them were GOOD singers with interesting personalities, while the 4th made up for it with a pretty amazing personality. The only thing that sets them back really was they were too shy when they first started, when they needed to be upbeat to bring in fans. I'll give 9th Gen credit, they are amazingly perky, which puts them one point above 6th. However, the talent that stemmed from 6th is pretty amazing
The reason I say 10th is so strong is because they resemble 6th, EXCEPT they are talkative! We have Haruka, the sarcastic and snide kind of take-no-bullshit character we saw in Miki. She also has a VERY unique voice (Like Miki) and had a fanbase going into MM (Like... Miki). I see her becoming a lot like Miki in the future, with lots of lines and a snarky personality.
Ayumi reminds me of Reina, though mostly for being all around decent - not really personality yet. Reina was a decent singer and a decent dancer when she first got in, which Ayumi has the advantage of being. Ayumi is great, but personality wise she's the weakest and I'd like to see her take on a stronger personality. Lucky for her, she makes up for it by being VERY talented. I also love the Riho vs Ayumi fandom wars she's causing, which will make her more popular in the long run.
Masaki is Eri. Stupid and Shy lol. Masaki does really weird things that only Masaki understands... and that's a VERY Eri like trait she has. She also has a very sweet voice and can hold a tune.
Haruna is Sayumi. Now, I'm gonna preface and say Haruna is not the worst singer in the group and isn't actually a bad singer, but of her generation she's definitely the weakest. With that though, she's super talkative, always has something relevant to say, and is really pretty. She has a very awesome personality that I think will grow into something Sayumi like, since Sayu is her idol.
Anyway that's why my ranking is what it is. The only reason 6th gen isn't second is because of my bias for the Pandas