I currently use the Galaxy Note 2 and at first thought it would be a monster to use but I've always gone by the old adage of "Don't knock it. till you've tried it!" so I'm trying it. I have used iPhones from the original to the 4S, all the Nokia versions, Motorola Razr Android, Windows Phone 8 etc. etc. ok, it's my day job to test/use them.
I think it boils done to What you're using/needing the smartphone for? If it's making calls, surfing the net, updating Twitter. FB. Pinterest etc. iPhone sized screen size is great and does the job. Now if you're using the smartphone as a business tool and replacing your laptop or tablet - uhm...you may have to try a bigger screen. For my work using the Galaxy Note 2 with a 5.5in. display has been a revelation for answering emails, checking document attachments, and reading and annotating PDF files. All much to my surprise. This "PHABLET" - phone + tablet - device has surprised me in proving so much more utility far out weighing it's larger size that it's a keeper!!
So again, it goes to the question of your "needs"? I now do not carry my laptop and can successfully manage all my emails and editing documents on this device when travelling.