Personally, I've used many different GPS brands but I have only ever owned Garmin (we are on our 2nd). I've used Magellan, I've used Tom Tom. I find Garmin to be a bit better, overall, than either. Magellan has done quirky things, and Tom Tom, a little too "user friendly" for my taste along the line of the old adage; if you make something foolproof, only a fool will want to use it.
As for traffic info, I find that feature to be one of the least useful. It is a rare occasion that one just "happens" on a traffic jam without notice, and the very infrequent times that does happen the feature is hit or miss on giving adequate warning, regardless, and worst case using a system without the feature or one with "not the best" version of said feature is about the same - your worst case is that you get stuck and a few minutes (on average) you take a side road and drive for a while off course, using your head, until it reroutes away from the road you were on. Not too difficult.
Of course, I don't live in an area were the traffic info would make a huge difference. I guess if I lived in or worked near a large city and had a commute in or around it, and there were several routes to choose from, and traffic was variable most days, then it might be a good feature IF it worked.
So, I would recommend Garmin, primarily for price versus performance.
TJR