I'm very unhappy with the new format. I cannot view as much content on one page, there seem to be more ads encroaching on real estate on the right side and top (slowing down page loads, contrary to the stated intent of the upgrade to speed things up), and the mobile view is gawd-awful.
The mobile view default is also reluctant to let me revert to the non-mobile version when viewed on an iphone. The links don't respond when you select the classic layout until I try a few times to click on them or orient my phone 90 degrees right/left a few times.
In summary, the old layout seemed tighter and more refined, more content was viewable, ads didn't take over nearly half of the screen, and the mobile browser didn't intrude.
Thank you for your feedback. What iphone are you using and is the IOS upto date? I have an iPhone 5c and it appears to be working when switching from mobile back to non-mobile view.
Also, try clearing your cookies and cache and make sure you are logged in. Let me know if there is any change.