The large amount of Apps
Camera is quite good
Touch screen is brilliant
Obviously it can not go without saying that receiption has been widely reported - I have had no issue what so ever with this though.
As mentioned the inability to play flash is annoying, but not a deal breaker by any means.
I just want to start out by saying that I have never used an iphone before making the plunge to get the iphone 4. Before I have always opted for camera phones.. so in other words the phones with the best cameras on as I have never owned a digital camera, and it seemed a good idea to combine the two considering I always carried my phone with me.
The functions I desired in a phone changed, so I decided that I would be happy to take a downgrade to my camera on my phone, and would want to make more of the email functionality and web browsing functionality (I had only had 3g, and had never had wi-fi on my phone) as I wanted more of a laptop on the go.
The absolute best thing about the iphone is the Apps. If you think you need something, you can go to the app store and usually get it. This means that if you need converter for your job, you can get it. If you are a compulsive gambler, you can get brilliant Apps that lets you gamble on the move. If you are interested in the stock market, and need to see the most up to date quotes, you can get them. You can also get some pretty good analysis tools as well, which is a big bonus (can you guess what I do as a hobby yet!?)
The iphone is a great little bit of technology and the touch screen is far superior to the other touch screens I have had before. A much bigger screen than my previous tocca ultra (terrible bit of garbage of a phone!) and my LG Viewty (superb phone!) and the clarity is brilliant. Considering the tocca ultra was costing me Â£10 less than the contract I am on now (excluding wi-fi, and excluding inclusive 3g access- the iphone has 750mb which is plenty for me!) I have realised just what a rip off my Samsung tocca really was.
The downside to the phone (and it is actually quite a big one) is the inability to run adobe flash on it. Considering a massive amount of websites use flash, it is really disappointing the Apple refuse to allow it, although you can jailbreak the phone- it still costs too much to risk at this point in time. I have a 24 month contract at Â£45 per month. This gives me all the wi-fi I need (unlimited!) and 750mb of 3g as previously stated, it is more than enough for my needs. The videos on youtube do tend to load quite slowly, but I am not on there loads, so not a big problem.
All in all, I can honestly say I really do not know how I got by without my iphone 4, as I am on it constantly for business and pleasure. It may be too much for some people though, especially if you are not going to use all the functionality offered. It is definitely a short cut for me though, and I could not be happier with it!
Go for one if you can afford it, although there are now android phones which can do more than the iphone 4, test everyone to see what fits your need best. The HTC phones seems to be very popular.