OK I've been to them all - it's all about the food right ?
Anyway here are my thoughts :
Bomas
This is a buffet which I enjoy greatly but I have been with friends here before who aren't over keen on the range of food - a lot of it is very different buffet fare but they do a great range of dips, salads and soups and wonderful desserts. This may be a risk depending on your guests tates but out of the 4 you've picked it's certainly the cheapest
Jiko's
Very very good. I've had probably my best filet and definitely the best Mac'n'cheese ever here. Wonderful food and fantastic service, but again I'd suggest you check out the menu.
Artist Point
I do like the Artist Point but would agree with Ellie that there isn't the greatest amount of choice. The buffalo is very good and the salmon is again some of the best I have ever tasted. The cobbler for dessert is wonderful but you definitely to share it.
Wolfgang Pucks
This would be my favourite out of the list you've given - mainly because of the variety available. The menu is extensive and they also have daily specials as well. The sushi is the best I've had on WDW property. Their sandwiches are huge. Flatbreads are very original and tasty. Great pasta. The butternut squash soup is heavenly. Oh and they do a wonderful chocolate fondue for dessert.
Yachtsman
As Ellie mentioned this I just have to say that this is also one of my favourite restaurants but I think the choice of appetizers is lame but that's OK really as the entrees are huge and more than enough but my DH and I have big appetites and I do like more often or not to have an appetizer, entree and a dessert if I can squeeze one in.