I have an older Burley Dee-lite, and it's worked quite well. It also has some storage space behind the kids' seat, which is nice. Easy to get on and off the bike, too, without the need for any mounting hardware to stay on the bike.
As far as safety tips go, two things:
1. Think carefully about your routes. Depending on where you live, and where you want to go, there are low traffic options. Be creative.
2. Take. The Lane. We do most of our riding with kids in tow in the East End (East Liberty, Shadyside, Highland Park, Morningside), and I always take the lane. Most of the time, I can find space to move over to allow cars to pass, but my preference is that a driver doesn't think they have enough room to pass me and my trailer. They can wait a minute 'til I can get out of their way.