I have an off brand clone of the BOB trailer and it is great for errands as well as touring. You will want to do some test rides with increasing loads to get a feel for how it handles. Cornering is a little different as are hill climbing and descents -- nothing that is all that dramatic, just different. After 2-3 rides with different loads I no longer noticed the trailer in most conditions.
One thing that can make it it even more useful is a large Rubbermaid type container in the trailer. That lets you pack more groceries in a dry box, and just use a bungee to hold the cover on. I have even put a large garbage can in there to do trash collection on the MUP I use, I have hauled shovels and other tools around for trail and other projects. The only real limit to its uses are you imagination and DIY skills.