Pros:
* Really high sensitivity. Now it always works inside the car, and it always works when hiking in the forest. You can just drop it into your pocket or backpack.
* Routing capability. Very useful if you have a good map, even if it doesn’t give voice commands.
* Color screen rather than B/W makes it much more readable even if screen area is slightly smaller
* When saving Waypoints, now the date and time info is automatically included.
* Battery lasts at least twice
* Rapid transfer of maps and tracks through USB rather than serial!
* Compatible with the maps and logs that I already have. I transferred all the waypoints and tracks saved in my old Vista to this new model, through Mapsource without problem.
* Compatible with my car, motorbike and bicycle mounts that I already have from my Etrex Vista.
* I can still use the free maps that I used with my old Vista, from: http://mapcenter.cgpsmapper.com/catalogue.php and from
http://www.malsingmaps.com/ ;
* Automatic date setup (from the satellites?)
* When transferring to the PC, the Active Log is now transferred as a few tracks (I guess one for every time that you have powered up the device) rather than as a long list of tracks
* When saving a track, now you can decide exactly up to which point to save back.

Cons:
* Not compatible with two of my Etrex Vista accessories: Car power adaptor (now the power comes through the USB connector) and Garmin case (now the unit is a little bit wider and shorter)
* No Favorite Waypoints menu. Has been replaced by a Recent Finds Menu?
* User Interface is sometimes confusing and not easy to find the function that you are looking for.
* WAAS setting and backlight level get to off whenever you power off the unit rather than remembering the setting (firmware bug?)
* Product Manual is very bad. It tells you how to turn things on and off, not why and when you should turn something on and off.
* No Micro SD memory included so you cannot upload any map unless you buy one.
* For the next product update, could I ask Garmin to add a Voice Recorder function to be able record a voice note associated to each Waypoint?

REVISED 6/30/08: Okay, finally! I got someone at Garmin customer service (very nice in the Mac Dept.) that could explain what-exactly needs to be done to get this puppy up-and-running: I had already downloaded the Garmin MapIntsall software (which you need to open, then select the device-in this case the HCx); there you will find all your maps (in my case the Topo Natl Parks and Topo USA for Mac). With the GPS plugged into USB port you simple select all the maps you want from one set of maps and then go to the other set and select the ones there). Works like a dream! Now if they would just make this clear somewhere (and believe me, it is not CLEAR anywhere). That being said, the experience I had today was much better. While I had to wait another 30 minutes to get customer service (who told me the serial number is located inside the battery case on the back) and then another 5 minutes to get to the Mac specialist-all my questions were answered! Both techs were very nice and helpful! Today’s experience would be 5 Star Customer service! while I have rated the device 2 stars-I would probably change to 4 stars. Why the missing star? Initial frustration that could have been alleviated if Garmin took the time to stuff some extra instructions in the box specifically for Mac user’s and made their website a little more friendly-and informative. The 24k NATL PARKS maps are beautiful on the color screens-as are the TOPO USA 2008 for Mac. The toggles are still awkward and unruly-but I’ll get used to it. So, in a nutshell; You can download multiple maps on to your Garmin Vista Hcx using MapInstall (dowload from their website) to your applications folder. Once downloaded, connect your HCx to USB and select device and have fun selecting your maps. One thing I was not real clear on until today is that “Bobcat” is strictly for viewing maps and transferring wayspoints, etc. It has nothing to do with uplading maps to your GPS. Use MapInstall to upload maps to the GPS. Today’s experience brought my faith back in Garmin customer service and technology. Thanks Garmin, for FINALLY becoming Mac compatible. I’m going to be a happy camper with this wonderful little GPS!

REVISED 7/6/08: Referring to the most recent “1 Star” Review; Yes, mine locks-up/freezes, too (nothing to do with Mac) unit freezes on the trail-at least once a day. No response from any buttons-unable to do anything until holding power button for long period-reboot. This is not cool! Will call Garmin Monday and see what’s up. Not good to hear they have a new chipset out and this may be the old one. After-all, I just purchased this. Will report back on what Garmin says. This sounds like an obvious defect.

REVISED 7/9/08: Emailed Garmin Monday-no response yet (3 days later)-so returned to Amazon for exchange. Amazon is great! No problem. Sent out a new one before I could box up the defective one-received replacement today! That’s customer service! Will let everyone know if the problem persists with replacement unit. Amazon 5 Stars! HCx?..not so sure anymore.

REVISED 7/11/08: Garmin emailed me 4 days later and explained that the new chipset is 3.0. My software version is 2.60. Used “Web-Updater” on my Mac and said I have the latest software. Everything is working beautifully with replacement Amazon sent me. No freezes or problems of any kind. Final score: Garmin HCx-4 Stars! Amazon-big 5 Stars!