HP iPAQ 5550
Introduced in the summer of 2003, just after the iPAQ 2215, the HP iPAQ 5550 PDA is HP's new flagship PDA, replacing the 5450. The first word that comes to mind is "excellent", and the HP iPAQ 5550 aluminum case is all that the 5450 should have been and more.

While the 5450, which HP iPAQ 5550 strongly resembles, had most of the same hardware features and used the same casing and design, it suffered some bugs and reliability issues when it first came out.

HP iPAQ 5550 runs the new PDA 2003 OS (also called Windows Mobile). PDA2003 is based on Windows CE 4.2, while prior PDA and PDA 2002 PDAs were based on Windows CE 3.0. Microsoft is calling all new devices based on PDA 2003 "Windows Mobile 2003.

The HP iPAQ 5550 has an Intel XScale PXA255 processor running at 400 MHz. The 5450 had a PXA250 processor also running at 400 MHz, and the PXA255 is supposed to be a bit faster (thanks to a faster system bus) and more power-frugal. The HP iPAQ 5550 does feel considerably faster, though those speed improvements may be due to OS improvements and bug fixes more than the processor change. Interestingly, the more affordable iPAQ 2215 shares the same processor as the HP iPAQ 5550 but benchmarks seem to be a bit faster in several areas.

The HP iPAQ 5550 has 128 megs of RAM, while other high end PDAs have 64 megs. Like all PDAs, that memory is divided between the OS (like RAM in your PC) and storage space (like your PC's hard drive). The PDA has an application that allows you to adjust the balance between these two using a slider, and generally allocating 30 to 35 megs to the OS (called Program Memory by the PDA) is plenty.

The HP iPAQ 5550 PDA offers the same auto brightness setting as the 3900 and 5400 series models, where the iPAQ measures ambient light and adjusts screen brightness accordingly. While the 3900 series could be annoyingly fast to react to small changes in ambient light, the HP iPAQ 5550 handheld PDA has got it down, and most users will find it great for viewability and power savings. The cheap HP iPAQ 5550 PDA, like prior high end iPAQs such as the 3900 and 5400 series models, have the best displays among PDAs.

HP iPAQ 5550 battery is a user replaceable 1250 MAh Lithium Ion battery. Battery life depends on your wireless usage. If you don't turn on the wireless features, you should get about 3 hours actual usage per charge, which puts it at middle of the pack for PDAs. The discount HP iPAQ 5550 PDA would get will make sure that you do not pay much for all these features.