Gasp!  Yes, CA readers, it's true:  About last Friday or so, I decided I would take the new Gmail challenge and dive into the new interface.  In other words, I decided to use the new look for at least a day or two to decide whether I would really 
get used to it, as I had heard others report they did.
As a former critic of the new 
appearance, let me say I now strongly prefer it to the old look.  DOUBLE GASP!!  Ironically, one of my biggest hangups became, perhaps, my favorite feature:  The minimalism.
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| In the new-look Gmail, t's all about the emails, peepers. | 
That's right, kids, the new interface cuts straight to the email.  Some complain there's too much white space.  I'll tell you what, click on the big gear and select Compact -- that will display plenty of emails.  On the other hand, I really like the "Cozy" density and cringe to think of the stress on my eyes, reverting back to compact-style.
And, talking of white space, here's a further irony:  Getting rid of many "buttons and knobs" (thank you, Arthur Weasley), I feel more comfortable and focused on my email.
In short, when I went back to take a peek at the old Gmail, my eyes felt strained, and I felt stranded in a cluttered garage.
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| Yes, the old look's more traditional and has less "white space," yet, consider its comparative clutter. | 
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| Ahhh.  Now my eyes focus on the email (because, seriously, why would I want to focus on my chat search box, etc.?) | 
I'll be candid in saying I feel hesitant about the degree of transparency on some themes, like Turf.  Yet, maybe that's just me or, like my conversion experience, simply an initial, gut reaction.
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| I imagine some might like less turf behind their email. | 
At the end of the day, users still must 
opt-in to use the new-look Gmail, and this after about two or three months out of the gate . . .  I'm unsure what the hold up is.  On the other hand, I definitely suggest giving the new look a shot for a couple days and then comparing/contrasting.  I definitely think old habits can die hard, 
especially in Gmail land (see the comments and be warned of some potty mouths).  So, take a chance, and if you also decide to make the switch, I hope your diet will be crow free, unlike mine.  Provecho!