Which one would you choose for daily ulcer prevention? Horse currently has no issues with ulcers but has a history of them.

I didn't have much luck with either one for two of my horses.  I have tried a lot of different ulcer prevention stuff.  I have seen amazing results going to Ultium Gastric care and Platinum Preformance GI.  They are always eating and drinking at the trailer now and handled our overnight much better then last year.  My gelding had bad ally issues. They aren't gone, but much better now, and he ran in the 2D with over 350 entered both days last weekend.  Good luck. 

I think the Purina Ultium has the outlast in it. One nice thing about outlast is if you have a horse that doesn't need a lot of grain they make the outlast supplement and now have cookies. My mare is pretty picky but really likes the cookies!

Yes, Ultium Gastric has Outlast in it!

i love the idea of the cookies, but you have to feed so many of them to get the full serving of Outlast. 

LOVE outlast. I tried U-Gard with no results. I really liked G.U.T. also, it worked well on the horse I used it on. Haven't used it since using Outlast however. I give just 2 cups of it before riding, hauling or competing (about 2 handfuls). Mine eat it alone like grain and they love it. I also love adding Forco along with it for added gut support. 

I'm feeding the Purina Impact with Outlast in it plus adding an additional 1 cup of Outlast.  I also have the treats to use before running.  Sometimes I just put the regular Outlast in a bucket and feed that instead of the treats, it is cheaper that way.  All of the alley issues aren't gone (she hates holding pen setups) but I do notice a big difference in her.

I feel like you have to feed so much grain to get the outlast that way lol. I have VERY easy keepers and we have excellent hay here in CA.  I feed the outlast in addition to Enrich and like to add a cookie here or there before trailering or at a run etc. 

Sounds like Outlast is going to be the winner.

I plan to feed Renew Gold and Hayrite Alfalfa pellets, too. I'm so confused about the dose for Outlast- if she weighs 1,000 pounds, do I feed two cups per feeding (two times a day) to get the right dose?

I feed 1 cup twice a day, and then if showing I'll feed 1 cup during the middle of the day. 

Mine is getting 1 cup 2x's a day plus either 6 treats or 1 cup an hour before race.  This is in addition to the outlast that is also in the feed.