Summary: Works just fine for me. I have used it for about 1.5 years and there have been no problems. If you are comparing this to a high end $250.00 or above GPS systems, yes, it falls short. But it is definitely usable for everyday purposes.
Summary: I liked this product before but the new update has made this a real winner. When I first got my Worldnav I was going to Nebraska to visit a new customer, it got me there even with the last 6 miles of the trip being on dirt roads.
Summary: WorldNav (version 4, Premium model) device is well constructed. It has a SIRF III chip set that makes my GPS lock in very fast. The screen is very clear and I could see it even during the direct sunlight. I took it on a 200 mile trip around the northeast. Voice instructions clearly pronounce the name of the street to turn onto, with just the right amount of time to make the turn. Routing is just about perfect.
Summary: I am agree with the other reviews: The turn locations can be quite off and the street names can be off. I have been testing it with my wife's Magellan I brought 3 months ago. The Magellan and the Teletype Premium side by side had interesting results. Even with the Teletype having 12 million POI, the Magellan showed me like 35 points of interest (in real time) by Disneyland, CA. The teletype unit showed me 1 gas station (in real time).
Summary: I got this GPS for $325 in November 2006. First few weeks were a nightmare. Upgrading from version 3.06 to 3.11 took about two months. This GPS is really a piece of work. Maps are very old - maybe 5-6 years. Always getting the message "searching for route" . You have to keep moving to get any directions. When you stand still it doesn't respond.
Summary: Well, I received the 3100 XL Premium on Thursday (11/17/06), updated to 3.09 and reset values in POIs. Played with it for about an hour out of box to get familiar (I HIGHLY RECOMMNED THIS, SINCE IN CAR IS TOO DANGEROUS...also this part of the learning curve!!!) and took it on the road over a long weekend (Fri-Mon.) 500 mile trip. In short, I loved it! I live in rural Indiana and the unit was great at tracking my movement even in this remote area.
Summary: I have had the Worldnav 3100 premium edition about two weeks with no problems. Lots of features for the price. I'm sure many of the problems I read about in reviews were corrected with upgrades. The only negative I can see is the cost of a external antenna which cannot be purchased anywhere else.