I've been to Porchetta a few times now and am usually pretty happy with my food. Sometimes its a hit or miss, but even when its not the best, its still decent.
The best thing I have had from porchetta was when they did the softshell crab sandwich. Unfortunately because this is a seasonal item its not there all the time.
I like to get the sandwich pretty basic with just hot sauce and both kinds of mustard as some of the toppings can be pricey.