Personally I like the old standard 375 H&H.
The Ultra and Weatherby use a heck of a lot more powder and compared to the H&H knock the snot out of you for marginal gains IMHO. A hanloader could squeeze more perfomance out of the H&H if they so desired. Let's face it a 375 class round is not used for long distance work and most shot are inder 200 yards with these and most likely in the 75-150 range. I don't think an animal will know what hit them ,but if you're into S&M and spending long green on ammo by all means by an Ultra or Weatherby.