I have had a Garmin III for a while, and used it stand-alone and with laptop in vehicle, so I knew what (somewhat) to look for in the technology.
My purpose was to use GPS technology on my motorcycle for cross country trips.
Pros - iPaq HPrx3115 and HP iPAQ GPS NavSys worked well together. -Devices were physically sound, and even with vibration on the motorcycle didn't miss a beat.
-Could not hear the voice directions, but could read the display to see what the voice had said..., -Though there is map update available from NAVTEQ (New name for Nav Tech) the one I got with the unit worked well. -Used vehicle chargers on both units keeping brightest display on the 3115 was essential during the day. -Used RAM RV handlebar mount for 3115, while NavSys housed well in the tank bag, along with cell phone. With added helmet speakers, the voice was audible. -RAM mount allowed mounting close to LOS (Line of Sight) which is important when driving a motorcycle, and -the auto zoom in feature was great. It's really hard to read a map while riding a motorcycle. -Setting route traverse up rather than north up, was a real plus, because the map matched the roads I was on.
Cons -have to shut down the nav program on the 3115 BEFORE powering down the unit. -Loading new regions was time consuming and had to be done at home, no way to update on the road unless I carry a laptop, no way on a motorcycle. -Can't route the trip on the host PC with the NavTeq software, has to be done on the iPAQ. -Twice routed me to an exit, then cloverleafed me back on to the same route and direction. -Once came to a detour it didn't know about. Bridge out, had to circumvent it manually, but had to restart Nav program to get to right place on the map. -Had to turn Off the WIFI access, as it's hard to dismiss a window with heavy riding golves on, and dangerous as well.
Summary - It took me most of the trip from Minnesota to Tennessee and back to learn how to use this setup. I'm not really excited about the price of the map updates - $99.00 USD, and available every 6 months for US and Canada. But I guess if you really need the latest for an important trip, they are very detailed. Never did figure out how to use POI (Points of Interest) without losing my calculated route.

I have an old Garmin etrek, which is a very basic and robust GPS. I always complained about the time it takes to find the satellites, but this HP device takes a lot longer!

Even in open areas under blue sky, it takes several minutes to operate properly. I tried it in San Francisco, Chicago, Miami, and also in Brazil, where I live. The result is always the same: you walk or ride for a long time before it finds your position. Quite disappointing.

Buildings and eletric cables interfere a lot with the reception, and very often you will lose signal. Bluetooth connectivity, though, works fine.

Having a GPS associated with a PDA (I have an iPaq 4150) is great: there are great softwares available. But life would be a lot better if this unit was more sensitive. I wonder if other brands and models work better.

(by the way: the navigation software is very good)

I have had this GPS Reciever for a month now, and it works very well. Sometimes it may be a little slow in getting a GPS signal, but the software is pretty good. Sure beats buying an in car system (the built ins from Honda, Infiniti, Nissan, etc) cost almost $2K! I paid $275 for this and another $290 (about) for the actual PDA. I think it's a really good deal. Plus I get wireless (iPaq rx3115) and all that other good stuff. All in all, a very user friendly system. Intial problems with set up have been solved with the help of the dedicated iPaq support line, which has been very friendly and nice. Surprising service for a technology company, in my opinion.

I ordered and returned this item 3 times from Amazon, each time I was sent a returned/used item!! Units had scratches, missing accessories and manuals. Apparently this item is a popular "use it and return it" item. Amazon apparently does not QC so check your box carefully.

The Hp Gps unit is a good buy, It has its pro's and cons. But overall is a great buy. Don't pay more than $200 for the unit though. Pros: The unit is small and easy to operate, Connects quickly and reliably,software is great and fairly reliable.
Cons: The holder as many have writtin is cheesy and cheap, it rocks when you make corners and requires you to tape a button with double sided tape to the back of your PDA. I would reccomend a different mount and one with a speaker like the ARKON Powered PDA & GPS Mount Kit listed in another review. I would also reccomend using velcro to fasten the gps unit to your dash otherwise it slides around. As far as using the gps for walking, it is a bit of a pain to use unless you put it in a T-shirt pocket, anything thicker than that and it wont recieve a signal.I sewed a velcro strip to my jacket and stick the gps to that. Also I would reccomend having at least a 256 or 516mb memory card in your PDA If you plan on travelling state to state. I put 5 state maps on my pda and it fills my 256mb card. So the more memory you have the farther you can go.