That link doesn't work for some reason (it always redirects to some, uhm, other picture). Was Star Wars'ed (fixed in editing ). But yes, the context the quote came up in applies in full for Love Live! and its fans, although K-On! and Love Live! share a writing credit to which the similarities can be traced back to, but writing decent or good episodes for one show doesn't mean you come up with good ones or good ideas for others. Just look at the Utena episodes and Sailor Stars, they shared like half the writers.
Very much. K-On! has a few weird things* in its first season, but that's over fairly quickly, and in the second season it's finally put to rest when Mio knocks out Sawako. K-On! was genuinely funny at times, heartwarming at others, and very occasionally somewhat sad. It's something silly you turn on for a bit of a good time, nothing too serious. The biggest hurdles really are the weird things in the first season, and getting through Yui's and Ritsu's constant overacting phase. The show really improves its balance after a few episodes.
Before K-On!, I didn't exactly enjoy Love Live!, but at least I didn't actively dislike it. It got some laughs here and there, and that episode where Kotori almost leaves for a different school has a very ripped-off-from-Sailor-Moon vibe, but it was a nice enough episode. Now... I don't know. Maybe the two episodes were just bad, but the feeling that I'm watching a worse version of something that I found genuinely funny and actually great at times (not often, but every now and then) is always there and doesn't seem to go away.
edit: Love Live! is really strange. The last five minutes of the episode suddenly stop being about this ridiculous weight loss plot and become about Honoka, Kotori and Umi making a mistake with the student council budget requests and working hard to find a compromise. It had a funny joke, a fun ending and it led to some character growth. It's like a SuperS** episode that would be genuinely good if you'd just remove Pedosus from it.
*That I mentioned already, anyway. Like Sawako pulling Mio's pants down for no reason (well, the "reason" is that she got dumped on Christmas). Wait a minute, let me check something. Nope. That epsiode was actually written by the series main writer, not the guy who later made Love Live!.
**I just realized that you could just pronounce that Super-Ass and... yeah. SuperAss. I think that'll be the term for SuperS in the future.