London - In our previous article Smartphone Wars: Nokia N900 versus HTC HD2 versus Motorola Droid (2) , we have seen that the most formidable iPhone challengers aka. Nokia N900, HTC HD2 and Motorola Droid can all slug well and are champions in their own rights.

However, no smartphone is a perfect one (perhaps that's why they are all called smartphones and not perfectphones, duh!) and they all have weaknesses that others can exploit.

For instance, the key letdowns of the N900 are:

* The N900 scores poorly in design and it's not the prettiest of devices on the market. The phone comes only in black and resembles an old-fashioned cigarette pack and is missing the sleekness of other smartphones, especially the iPhone. Not surprisingly, according to research firm CCS Insight, the N900's "uninspiring design further reflects its experimental nature and signals that the appeal of the device lies more in the software platform than the hardware";

* Though the N900 works fine in both portrait mode as well as landscape mode, at the time of testing, the portrait mode is exclusively meant for the phone calls i.e. dialling the number on keypad, or selecting a contact to call. It does not even extend to SMS and even for the shortest message, you have to switch to landscape mode;

Also though some applications work also best in a portrait mode, it is impossible to make them do so in the N900. However, fortunately, it is not some strange aberration on Nokia's part. Probably, they simply did not have enough time to include that before the device launch and a Nokia spokesman said that the problem will be fixed in time and the company will include portrait mode support in the N900 browser by the end of the year, with pervasive portrait support throughout the device later;

* Though Maemo UI is marginally better than Android and is crisp and clear, yet it still does look dated in comparison to Apple's iPhone. In fact, the biggest problem with the Maemo UI is that it isn't unique enough. In fact, it looks somewhat like MotoBlur - a screen with a lot of widget-styled apps. And, it also uses multiple desktops and also multiple screens, which makes the user experience slightly confusing;

* Entering password on the N900 can be very annoying. Usually, on a mobile device, when you press a key entering hidden symbols for a password field, the actual symbol pops up for a short while, and then is replaced with a star.

This, however, does not happen with the N900 browser when you're using the physical keyboard to type in a password on some site. This can be frustrating as often when the password does not work, you are left guessing whether you forgot it, or just typed it wrong on those tiny keys. And, trust me, trying to figure out which one it is, by entering password again and again, is no fun, and can leave you banned from some sites for hours.

Fortunately, however, this problem does not occur when you are using the virtual keyboard instead;

* The keyboard on N900, despite being in landscape layout, is surprisingly cramped and it is difficult to type on its tiny keys with big, chubby fingers. The virtual onscreen keyboard is, however, extremely responsive and promises error-free typing;

* I don't know if there is any easy way around it, but moving shortcut icons, when customizing the desktop panels, can be very annoying sometimes as the ratio between icon size to "close" button size is really small and while trying to move an icon in some other place, one can accidentally delete it;

* Call me biased but I'm not a great fan of the resistive screen and as such found interacting with the N900 via touchscreen extremely painful. Believe me, if you're used to a capacitive touchscreen, stay clear of the N900;

* Ovi Maps 1.0 in the N900 that we tested is kind of "okay" but is a significant stepdown from the mapping/navigation experience especially when you are used to the much better OVI Maps 3.0 or Google Maps (fortunately, reports are in that the N900 will ship with Ovi Maps 3.0);

* Maemo apps currently available through Ovi Store, Maemo Select (http://maemo.nokia.com/maemo-select/) and Maemo.org Extras (http://maemo.org/downloads/Maemo5/) look sparse compared to those available in the Android Market and Windows Marketplace and looks almost barren when compared to the iPhone's App Store.

To find out what are the drawbacks of the other two smartphones viz. the HD2 and the Droid, click Smartphone Wars: Nokia N900 versus HTC HD2 versus Motorola Droid (4) .