The thing I don't like about technology comparisons - aside from the fact that they're generally subjective - is the way reviewers pitch competition in the market as some kind of death race where only technology can win. It's not like that, especially in the phone market - some phones are better for some things than others, customers have their own preferences and there's lots of room for everybody, with probably two billion phones in use around the world at any given time.
So my advice is to ignore all the predictions about the Windows 7 phone, and what impact it will have on the other players in the market. It's going to be big, market shares will adjust, but nobody is going anywhere.
While RIM has seen its market share decline recently, the Blackberry is still the phone of choice for businesses and governments, and that's not going to change - it would be like every office in the world suddenly ditching Microsoft Office for Linux. The Blackberry arguably offers the best security, people like the physical touchpad on many models, the push e-mail and text messaging options, the 4G phones and networks, the e-mail and productivity software, etc. The company has found its niche among power users that are less focused on games and whether they can use the phones to level a shelf.
As well, the phones are available through the majority of carriers and almost everywhere around the world - with the exception of countries that like to spy on their people and are frustrated by RIM's superior encryption. The announcement of the RIM PlayBook tablet is also exciting, and so far it looks like a pretty handy piece of hardware that the business set might happily embrace.
I would guess that RIM is pretty safe as long as they continue to play to their strengths.
Then we have the iPhone, which is a great all-around device that does things no other phone can do, or can do as well. It's a fantastic multimedia device and a great productivity tool with the right apps. But when all is said and done it's considered to be an average phone and business tool. A lot of people don't like typing on a touch screen, the lack of ports and removable storage, the price, the lack of options when it comes to push e-mail or text notifications, restrictions on tethering, the lack of 4G support or file access, or the fact that it's only available (in the U.S.) through one carrier. The apps are useful and getting more so all the time as Apple lightens up its proprietary focus, but business users still generally pick other phones - like RIM, because compatibility is important, and people want to use the devices that others are using.