Cobra
It is fun to use, has great versitility, and is easy to program. I can't ask for much more.

A product with a lot of flaws
This is my first GPS system so I did a lot of research online before I went ahead purchase it in March 2007. I wanted a large screen one and traffic system. 4500 seems to be the perfect match.

Pro: large screen, real-time traffic system saved me many times, and reasonable routing suggestions. I don't have the rerouting adaptation problem as the other reviewers and if I get into a side road, it'll recalculate immediately. Maybe they fixed it in the most current software batch. Their customer service is superb.

Cons: I had this unit for 5 months and have to return it now. As many reviewers said, this unit has slower routing calculation and I didn't realize it would be a problem until I was driving on a highway waiting for the exit.

Even though I have the most current database batch, I would see some not-so-new highways disappeared suddenly during the drive. It would come back eventually but it doesn't feel good to see yourself driving on a blank space for several miles, especially if you travel to a unknown place at night.

Road side of a destination seems to be wrong 80% of the time. We all know after 1 month of usage to ignore the final destination instruction.

After 2 months, the address book, all travel location information, and user settings were wiped out automatically and I have to reset everything. After it happened so many times, I called Cobra and they gave me another software patch. It seemed to fix the problem.

When used in big cities with a lot of traffics, its routing instruction can be so wrong. It usually gives me the worst routing suggestion, i.e. chose the busiest road, or a longer route, or use local highways with a lot of construction going on instead of an interstate highways that are much less congested, etc. This unit's routing logic seems to work better with mid-size to small-size towns.

The mounting is cumbersome. After taking it off and putting it back on whenever I have to park somewhere, the V12 cord connected to the car broke. I had to call the customer service and they sent me another cord immediately. Did I mention that their customer service is very good?

The final flaw which makes me wanted to return it is, one day the beautiful female voice was gone. Never come back again.

I feel sorry to have to put a bad review on a product. I hope it would help others to avoid the frustrations I have gone through.

nice if it works
I got the unit for Christmas, attracted to the good display, but leery of the reliability, both due to other's reviews. I have no serious references to other GPS units, aside from one in an ACRUA MDX that was built into the console, and was very impressive. My 4500 is away to be repaired now, they say for about 3 weeks, with very little use when it worked. I was careful with it as was possible and used it only on major highway trips.

I don't understand how, say an Acura, can have GPS that can sit out in cold and extreme heat, and survives daily driving, and the 4500 Nav One breaks while being treated like delicate china. I also bought every accessory that SHOULD have come with it for the price.

I hate to give bad reviews, but I have to say, if you need a GPS you can count on, this model is high risk. I would want to know this if I was considering buying it. The software can be a little bugged. I got stuck in some loop (it refused to lock in one zoom level) while on the road and eventually had to shut it down and reset to defaults. No idea why. It's sometimes not very precise and a little sluggish in real time rerouting, which can be frequent, as the unit gets lost for no apparent reason while cruising down an Interstate.

It does look nice, and has many great features when it works. That said, I had higher hopes for a portable GPS that really isn't portable, unless you have a portable power source. It was missed on my last road trip when it quit working, and will be missed while in the shop. For me the unit is more a toy than a tool fortunately, because as a needed tool, I would not highly recommend it.
update: Only took about ten days and got a new replacement for the crashed one. The new Nav ONE seems to perform better than the defective one did, meaning it doesn't get "lost" and recalculate for no clear reason, as before.

Cobra 4500
The unit is very large and bulky. It does have a very large viewable map which is nice. The unit I had worked about 1 week then would not power up. I am completely dissapointed with this brand and unit and am trying another one.

Cobra Nav One
I am very pleased with this GPS unit. I was alittle worried after reading some of the reviews, but am very happy that I still ordered it.

The graphics are by far one of the best. It has very detailed graphics, unlike many of the other brands that have a more cartoon look to them. The graphics are compariable to what you would find in a in-dash unit. It is very user friendly, and easy to navigate. The unit does weigh a bit, but have not had any problems with the suction cup as I read about. As long as the window is clean it works great. I have even drove over some really bumpy roads and the unit has not come loose.

For the money and what you get this is a terrific unit, and would highly recommend it.