Do you mean the USA set has a good bonus disc which is # 10 ?
Both sets have their own Bonus Disc, each with completely different titles. Although I don't actually own the UK Universal Collection, I am sufficiently aware of details regarding it to offer up a few reasons as to why you may not want to retire this collection as yet:
1. As you've mentioned in a previous post, the Essential Collection does not, for legal reasons, include any of the Laurel & Hardy Silents. Nor can they be currently obtained at anything resembling a reasonable price! Just check Amazon for your UK Set and the Lost Films Of Laurel & Hardy Volumes, and you will see what I mean!
2. While the vast majority of the Hal Roach sound titles look just as good or better on The Essential Collection, there are a few notable exceptions. SONS OF THE DESERT for instance, has some rather funky contrast issues, and actually looks rather terrible in spots. The best version I've seen of SOTD is the out of print German Kinowelt PAL DVD. While I don't care for the 4% speedup, I must concede that the much superior video quality (Not to mention no missing bits or Audio/Visual Sync Issues, unlike the UK Universal version!) is worth it, in this case!
3. If closed captioning holds any importance in your case, it should be noted that, while the Phonetic Foreign Language Films have English Subtitles, the English Language Films on the Essential Collection don't have either Subtitles or Captioning, while the opposite is true on the UK Universal Set!
In closing, my recommendation is to enjoy the marvelous (In my opinion!) Essential Collection, but hang onto your UK Universal Set, at least until a reasonably priced Laurel & Hardy Team Silents Collection becomes available (Whenever that may be?) in Region 1!