I've noticed the gate is slightly off level. I't barely if at all noticeable to most people. Anyway, I got out a level and checked the post next to the gate. It turns out that it is pretty plumb back and forth, but about a 1/4 to 3/8 inch off side to side (thus the gate being slightly off). The gate opens past a brick path that has a hump so that the gate on it's outward swing eventually just barely clears the brick--that's why the 1/4 inch is even relevent.
Anyway, another problem that has occurred is the latch is not aligned quite right so it is hard to open unless you first push in the gate. Also, it now has a strange "creaking" sound when opening.
I am going to have the guy come out and adjust the latch. However, I don't know if it's acceptable for a post to be slightly off plumb like that or if it is legitimate for me to expect a professional to get it absolutely perfect. Also, I don't know what could be done to fix it except to start all over.
What do you think? Is this margin of error exceptable or should it be perfectly plumb? I just don't have any experience with this so I don't know what should be expected in this type of thing.