I have used them a handful of times and I can only give a strong Don't Bother - you are much better off calling the restaurant directly.
I keep wanting Grubhub to work, but I find the same problems others do:
Wait times are ridiculous. Restaurant is less than 10 minutes away, if I am there at the restaurant (order at counter and wait for food type places), even if it is crazy busy it takes no more than 15 minute to get food and typically much quicker. Yet, the deliver time is 1-2 hours, yup 2 hours. Worse, you place the order and Grub Hub tells you on the receipt 45-60 minutes, and it is not until you get an email confirmation that it tells you it is much longer. Also, items often missing or wrong.
So, for Grub Hub to have value (versus you just calling the restaurant directly), they should be fixing the problems? Right? They have more clout as they are "bringing a chunk of business to the restaurant, not just one person).
Nope, they reply with things like well typically restaurants that deliver do so in 60 minutes (with nothing said why this one says it will be 90-120 minutes or any actions taken).
Or when something is missing they say - you should tell us this right when you get the food as the restaurant is closed now. Well I DID tell you right when I got the food, but they took so long to deliver it that they had closed by then.
Or they say well the restaurant said they are not refunding any money (on the messed up order).
So what is Grub Hub doing for you?
Providing another place for people to hack your information (they store all their information online and it "can't" be taken out as it is on all the receipts stored online and despite them saying clear your information you can't clear receipts)
Being a middle man so communication is poor - if you were talking directly to he restaurant on the phone, they would tell you deliver time right then and you could say never mind and choose a different place.
Giving out the wrong address so the delivery person is running all over trying to find you.
Not things I want someone doing for me.