Garmin updates the maps three to four times a year. Even with these frequent updates the maps are still about a year behind and even longer for places such as restaurants or stores. However, these updates are much better than never updating.
As far as live traffic with the standard Garmin traffic it is available only in the major metropolitan areas. The traffic does cover most of these areas in the US. In my opinion the traffic is usually accurate.
I am on my third Garmin in the past ten years to include a free unit Garmin sent to me at no cost when my original model could no longer be supported by their "Lifetime" maps program. I would not even look at other GPS brands.