Well there is a huge PRO: cheaper

but the con is not as many people will come and you may have less of a party atmosphere. If the wedding is on a Thursday you may be ok but a Monday-Wednesday wedding there will be a ton (maybe all of your guests) going to work the next day. Plus if you have a wedding party they may have to miss a couple days of work. If you just are looking for a dinner with not much party you should be fine though.