This is my second attempt to get to grips with a smartphone - the first a Sony Android device two years ago lasted less than a month before I went back to a proper phone.
I chose the 1320 specifically because of its larger screen area so that I could do some blogging and facebooking on a cycling trip as well as use it in place of having to carry my kindle as well. Fortunately I did decide to take my proper camera.
The worst thing is the battery life - if you leave it on it will need recharging after 2 days whereas my proper phone (a Nokia 2720, 6 years old) would last well over a week. However I gather this is normal (or even quite good) for smartphones.
Windows on a phone is certainly a lot more usable than Android (my proper computer is a Macbook not Windows) however there are many compromises. I can't get the calendar to sync 2 ways with either the Mac or a Google calendar. You don't seem to be able to set the default calendar to add events to - it is locked to the Outlook calendar. The camera is pretty rubbish - difficult to use and you can't upload hotos to Wordpress (there isn't an app for that apparently, there used to be but it not longer exists) which made it impossible to put pictures in the blog till I could get to a proper computer. The Facebook app works ok but is quirky so sometimes it is better to use the browser directly.
As a phone it works surprisingly well - voice quality is ok, speakerphone function is good, controls are well laid out. It is really difficult to look something up while you are on the phone though - for example to look up a phone number to tell to the person you are talking to, surely a very common function. To be fair this is not easy on ANY phone I have used and frequently results in having to hang up, look up the number, write it down on paper, and call the original person back - it should be a simple intuitive function.
The gps and map function works well, although the routing does not include a cycle option like google maps or velomaps and you can't edit the route once it has set it. You also cant set preferences (eg avoid main roads) for routing. I have a Garmin Edge on the handlebars for riding, although its small screen is not good for seeing an overview map but fine for routefinding within a city. The 1320 works ok as a replacement for carrying a paper map to use alongside the garmin - so long as it is not raining and you are not wearing gloves (the recent trip was both wet and cold)
There are three dedicated hard buttons along the bottom - back, home and search. Unfortunately the search button brings up something called Cortana which doesn't work. It would be more useful to make the third button configurable to give quick access to a specific app or function.
Email app is basic but works. You can easily set up multiple accounts or combine them. One black mark is that when replying to an email it always includes the original text and you cant edit it or get rid of it.
The Kindle app is rubbish, but works enough to be able to read a book. No search, dictionary, etc functions available.
Text messages are arranged in conversations per person which is good, but you can't delete individual messages in a conversation which is bad.
Despite its size it will fit in a trouser or coat pocket. You need to buy a flip case for it like this one Nokia Lumia 1320 Black Leather Wallet Flip Case Cover Pouch + Free Screen Protector & Touch Stylus Pen + Polishing Cloth
Overall I prefer the 2720 as a phone but will probably stick with this 1320 for occasions when I don't want to carry a laptop. I would still carry a proper camera and a proper kindle if I had space and weight wasn't a consideration though.
When fitting the sim make sure you hang on to the standard sized frame so that you can revert to a proper phone if you need to.