There are breed dissimilarities in every country becuase what usually happens is that the foundation dogs in the US, UK, Australia, etc. differed from both the foundation dogs and the ones used as outcrosses in each country. Unless the dogs from the US & UK are interbred on a regular basis, they tend to branch off and you will have a different look. I don't see either being better or worse, just different as certain bloodlines in any country will throw pups that are prepotent for a distinctive look.
Take Beagles in the US. We have two very different types just in this country, for field and show. Our field dogs differ greatly from the field Beagles that used to be bred in the UK. Both our field & show types are night and day from show lines in either country. If you took one from each type in both countries, it could almost appear you had four similar, but different breeds. I don't think there is anything bad about that. Variety makes everything better, even bloodlines.
Now, our US show Beagles are not as flashy or correctly built in the sense they resemble the miniature foxhound - the UK show Beagles have that perfected. But US show Beags tend to have a high degree of field ability, which I have not seen in UK lines at all. We also have Finnish lines in this country, which also have their own distinct, leggier look. It's all good, just a matter of preferences. I personally prefer most US dogs though, because of the high degree of breeding for dual purpose quality in our stock. It's illegal to hunt with Beagles in the UK so you know their hounds have no chance to prove themselves as rabbit dogs. I wouldn't touch UK dogs with a 10ft pole, then.