Of the three I've seen some of - AKB, Love Live and Idolm@ster, AKB would be the least favourite. I got some good laughs out of the hate mail episode and my friend yelling "Terrorist lolis! Yeah!!!" when they were sneaking past the security forces in the first episode, but for the most part I just couldn't get into it.
Love Live: I only saw one episode. I liked what I saw, but I only looked into it after it aired and I tend to barely keep up with currently airing shows since my time management skills kind of suck acid filled demonic donkey balls sometimes. Though I'm not fond of the series' way of handling the actual performance sequences. I find the 3D a bit jarring.
Idolm@ster: I like the characters, I like some of the songs and performances, and I liked the pilot episode and the episode the focused on Azusa and Makoto (the wedding modelling one). On the whole I found it pretty middling though. The two episodes I really loved are among the most... "chaotic" in the series and I think that's where the show is at it's best... one hapless dude trying to manage twelve hapless idols with wildly varying personalities. If it concentrated more on that I probably would have loved it.
WUG: I like it better than Idolm@ster so far. Because the characters feel like they have stories to tell, even if some of them (like the food lover girl's) seem a bit simplistic. And some of the characters feel quite "alive" - I keep mentioning Miyu, but she really does feel like the kind of girl I could run into at a anime con maid café. Which is why her getting harassed made me rage. Harassing maids is very NOT okay in my books. Unless it's consensual roleplay or something like that - then it's cool.
One other thing I'd like to mention: I think that as a general rule, I think tend to like idols but not necessarily large idol groups. I love watching Suzuki Konami's
winning performance at the 2011 Animax Anisong Grand Prix, both for her singing and because I think she's cute - knowing full well she was 14 at the time. But get a whole group of teenage girls dancing in short skirts and it just starts to feel "servicy" in a way I personally find rather uncomfortable to watch. I usually don't feel the same way about idol performances in anime, though some of the old Love Live music videos that got made before the TV series do capture the feeling.
(And this is entirely separate from incidents of exploitation in the industry. That wouldn't stop me liking the performances any more than being a environmentally conscious, pro-peace semi-socialist stops me from liking Ferraris and fighter jets.)