
There were some early rumors that the BlackBerry -- "iPhone killer" -- Storm was falling short of sales expectations and that there were a spate of returns happening. The early mixed reviews that the Storm received seemed to lend plausibility to those rumors. However, Verizon in the US was quick to try and dispel them. . . saying that the Storm, in fact, had "the lowest return rate" of any smartphone it sold.
BlackBerry has been spending millions on a media campaign to promote the phone but there are indications that it has not got the "legs" that RIM had hoped. The Wall Street Journal cites "people familiar with the matter," saying "the company sold roughly 500,000 units in the first month after the Storm's Nov. 21 launch. That is a promising start, though well off the pace of AT&T Inc.'s sale of 2.4 million iPhone 3G devices in that device's first full quarter on the market."
One of the major flaws of the device is that it doesn't have built-in WiFi. However later versions will probably rectify that error. The Bold by contrast does, and looks to my eye to be a more successful device in the near term and longer term for RIM.
BlackBerry is firmly established in the enterprise market and my guess is that the Storm is unlikely to expand its consumer base. On the one hand, the phone is too far removed from the tastes of its core users -- enterprise customers. On the other, consumer side, the iPhone, G1 (soon other Android phones) and the forthcoming Pre are probably more attractive handsets. (Windows Mobile plans a range of announcements of more consumer-friendly features.)
BlackBerry enterprise users like their physical keyboards, which the Storm doesn't have though it tries to simulate the sensation of clicking or pressing a physical key. While conceptually innovative, the experience turns out to be both somewhat awkward and unnecessary.
Early customer satisfaction numbers for the Storm were very mixed (and quite weak compared with the iPhone):

Source: Changewave (12/08)
The Bold will live on in the enterprise, but to really compete with the iPhone RIM may need to substantially modify the Storm (though a price drop could be modification enough for some).
We'll get more information on whether RIM's Storm is gathering strengh weakening on Tuesday when Verizon reports Q4 earnings.