Have a Galaxy Note II. Fits easily and comfortably in suit jacket pocket, but less so in jeans back pocket (does fit, OK for walking around, less so for sitting down).
I use MS Word and Excel via Citrix on it and the bigger screen is fantastic – you can actually read the documents and use full-blown desktop versions rather than the crappy word/excel mobile apps. Also good for viewing pdf files without having to zoom in and I can work from it on the go without having to use a laptop or tablet.
Battery life on the Note II is massive – it’ll take a full day of almost continual use. If you needed more, spare batteries cost about £10.
Also the big screen is great for using the built-in pen and the handwriting recognition is superb.
Netflix/iPlayer viewing is also much better than on my older/smaller smartphones.
Downside? You look like Dom Joly when you take a phone call 😆