I would say there is the biggest contrast between Hybrid Theory or Meteora and A Thousand Suns, but since it´s not an option, the biggest contrast of quality is between my 3rd best (Living Things) and A Thousand Suns.
There´s also a big contrast between those two, I just chose the other option because I can relate more to the songs of THP. From ATS I enjoy Blackout, The Catalyst, Iridescent and Burning In The Skies, but I still feel that THP is a bit more consistent, even though songs like The Summoning and Guilty All The Same are pointless to me, I think Until It´s Gone, Final Masquerade, Rebellion and Wastelands represent what a return to the roots should be and win over those songs mentioned for ATS, which also has some pointless songs to me like Wretches and Kings, Jornada Del Muerto, Wisdom Justice and Love and Empty Spaces (that one is not really a song because there´s nothing in it, at least Foreword from Meteora is much more intense and a cracking opener for that record). When comparing songs that to me are pointless or not in every LP record, that´s one reason why OML gets ahead of ATS and THP in my 4th place tied with MTM, it´s more consistent than ATS and THP.
I'd say between Meteora and Minutes to Midnight. With MTM they really kind of tore down every wall they built with Meteora. With the ATS and LT period, at least LP were still exploring territory like they did with Castle of Glass, Roads Untraveled... even Until it Breaks and Victimized. So it's not a huge a drop in quality or artistic exercise.
I agree with the second and the last statements, but have to say say that ATS to LT for me is the biggest improvement in quality.
For me it's like that, but I like LT, apart from the album quality in general, because it was the first LP record I bought and has that value for me.
I'd like to actually change my original answer to this thread. But I wanted to make a new post because I wanted to raise a point that I've become aware of, in my own opinion, over the last few days. I would say the biggest contrast in quality was going from A Thousand Suns to Living Things. A Thousand Suns was the last ''epic'' Linkin Park album to me. Living Things, The Hunting Party and One More Light are all sub-par to me, and I would say Living Things is probably my least favorite Linkin Park album. A Thousand Suns was actually quite an amazing album, and I never really realized that until recently. I was a teenager when the album came out in 2010 and I didn't know as much about music as I do today, and I think the lyrical content was also a bit too mature for me at the time. I also didn't realize how well crafted and executed the album actually is. I can't believe the band created an album like Living Things after coming off of A Thousand Suns.
For me, it's a toss up between ATS/LT and THP/OML. Both are contrasts are from awesome albums with political/anti-establishment messages and progressive elements that truly showcase how much talent the band has to watered-down and flat out boring pop albums with poor lyrics and lackluster instrumentals. I guess I'll go with ATS/LT, considering that I don't hold THP in as great of light anymore because of its anti-pop message which in hindsight is disgustingly hypocritical even just in the wake of the release Heavy, let alone the entirety of OML; whereas I still view ATS as still a brilliant album with a brilliant message.
For decrease or increase in quality? For me between those two would definitely be a big increase in quality from THP to OML.
Def ATS to LT. I enjoy Living Things (although it's probably the only CD in their discog that didn't get better with age IMO) but after the masterpiece that was ATS, it felt like a bit of a let down. I will say a solid half of the album upon release had me in Nu Metal type spirits tho Close in second is THP to OML. I enjoy OML but THP had such a solid direction (as well as giving me the angry adult LP album that I've wanted since post ATS) that OML never reaches imo. I absolutely love THP though