The Streetpilot i5 is my first GPS unit, so i would not consider myself an expert, but i do enjoy having the unit. Most times, it is accurate. You are able to store frequent destinations in your "favorites." To guide your way home, is a simple 2 pushes of the wheel.
Pros: This particular GPS has the wheel as the tool to navigate the menus. I thought it would be difficult to use, but actually, it was very simple. I like that it has a setting that if the car is in motion, you cannot enter a destination. The unit waits for the vehicle to be stopped. I also like that you can turn that feature OFF as well.
The screen while on the small side is easy to see, has a zoom option, and is in color with easy to see navigation arrows.
I like that when you enter the destination, it gives an approximate arrival time instead of "travel time."
cons: I do find that there are times that the maps don't seem up to date, even with older road construction. Currently, there are no updates available (but slated to be coming out this spring).
There are some confusing intersections that it is necessary to check the map and not just listen to the voice. For example, the device will tell you to "turn left" but it is actually the direction the main road goes, and if you were to actually turn, the route would have to be recalculated.
Update On May 10, 2008: I forgot to add that this GPS gives you the ability to look up food, local attractions, stores, pretty much anything you are looking for. As long as the destination isn't brand new, it can usually find it and provides the address as well as the phone number. I end up using this a LOT to find the closest gas station or McDonalds to where I am. It is a GREAT feature!
Update On Oct 25, 2008: The new update is finally available, and pricey. I couldn't believe they want an extra $70 to update the maps. I guess it is still cheaper than buying a new unit.