I'm born and raised in Ontario, and have hunted Whitetails here for several years, but I would LOVE to hunt whitetatils & Muleys out West. I've considered the option of going with a guide, and even contacted some of them, but at the end of the day, I can't justify the cost. $5000 for a 6 day hunt, not including travel costs??? Too much for me. Especially considering that with a little work and some networking, I can buy my own non-resident tags for Saskatchewan, or with a "hunter host" buy tags for Alberta. Sure, it takes longer, and may not guarantee the size deer that outfitters boast about, but in my opinion it's worth it.
Unfortunately comitments to my work have kept me from taking any hunting trips in the last several years. Hopefully this year I'll be able to go with a friend on his family's property near Vermillion AB, and I'm also looking at the non-resident gun season in SK.
I have to admit, the thing that bothers me the most about booking a guided hunt is the gratuities. I've talked to several outfitters, as well as a number of hunter's who have gone on guided hunts. It would seem that a guide EXPECTS to be tipped 20-50% of the actual hunt cost, even if you don't take an animal. I find this very distastful. A tip should be something that is earned, by going above and beyond what can be reasonably expected. I hate that tips are expected, even relied upon, in many proffessions now. For me to want to tip someone for doing their job, they'd have to take me to a new world record animal that they'd specifically scouted.
Since you mentioned Antelope, I think you might be interested to know that I looked at pronghorn hunts as well. If I do go to a guide for pronghorn hunting, it will be in Montana. From my research they seem to have the best rates, as well as the best chance of success.