Janak makes a good point... I've got a 5455 that was upgraded via PPC Techs to 128MB of RAM and I have a 1945 with a SanDisk SD W-Fi card (so I have a 4155, sort of... just go with me here...)
One of the things that I've noticed about my use with each of these devices has been that 128MB of RAM is a must for me. I am an all in one kinda guy. If I wasn't, I'd probably be carrying 3-4 different devices because this one does this, the other one does this better than the other and the third does something that the other 2 don't do at all... Honestly, if I didn't have a PC Card Hard Drive and PC Card Sleeve as well as a couple really nice iPAQ specific leather cases, I'd probably ditch my 5455 and new LG VX6000 cell phone for a Samsung i700 PPC Phone. Like I said, all in one, though the i700 doesn't have BlueTooth or WLAN built in...
If you're heart is set on an iPAQ, then let me offer this, as I've owned every series iPAQ (except the new 4000 series models):
The 5500 series is a good device, but big. If you have need of Consumer IR, this is a good choice. Its got both WLAN and BT built in as well.
The 4100 series is a good device. It has everything that the 5500 offers except 128MB RAM and Consumer IR (I think...) Its small, very portable, and VERY comfortable to use (the 1945 shares the same form factor...)
The 4300 is ok; but just as large as the 5500 and the keyboard is a different color than the rest of the device, something I REALLY don't like. If you're a Blackberry convert, this is going to be a great device for you. I personally don't want a keyboard permanently attached to my Pocket PC.
So... either the 4100 or the 5500 is a good choice, since they are essentially the same device (except for 2 specific features found in the 5500). However, you should know that its only a matter of time before Leonard from Pocket PC Techs (
http://www.ppctechs.com) comes out with a memory upgrade for the 4100. All of my devices have been upgraded by him, and they are really good at what they do. Upgrading the device later may be an option for you...
However, if you do that, and you have purchased the extended warranty, having the upgrade installed with void the warranty...
And about that, I don't know that I would go with the extended warranty. I've never had a device crap out on me, that wasn't my fault... check out
this and
this on pocketnow.com... Its funny but not. Again, thanks go out to Leonard at PPC Techs for saming my @ss.
I hope all of the rambling helps. Let us know if you have any other questions. We'll be happy to help out!
Kind Regards,
Christopher Spera