In speech both sounds very similar unless someone forces the pronunciation of the "u" and it you do this also with the "o" it all becomes kind of senseless.

The fact remains the "u" and the "o" are added vowels, added by translators and are not part of His Name.  If you check our the actual Hebrew characters you will see neither of these vowels are present and are additions to His Name

just as vowels are added to the Name YaHWeH, the "a" and the "e" are not in His Name, YHWH, but are added to help in pronouncing His Name as the translator understand it.  This is the same with the Name YaHshua, YaHoshua, or YaHushua.

Here is an update, and something this author is reconsidering.  This is something that has bugged me, on and off, for several years, something moving in an out of my mind -- why is the fourth letter in the name YaHWeH, called a Double U, you know, like two U letters, not two V, but two UU?  We find, then, that in Hebrew the pronunciation for the W is not as most pronounce it -- no, it is pronounced as OO, or as in UU, as we hear in some Israeli names like, Netanyahu, the Prime Minister of Israel.  Some, seeing this, want to apply this to our Savior's name -- YaHushua.  I find this to be as correct as, YaHshua.  Some reasoning I have seen is to carry this over from the Old Testament Name, YHWH, which if corrected to this understanding would be, YHUH.  I personally believe that both are correct.  And something more is common among all of the small variations -- it is the transliteration we are looking for, not so much a translation.  You know, how do you say it, not how someone things it should look in print.

You will notice the common denominator -- YaH -- is common to all of the variations this is the Name, YaH, the latter part of the Name is a definition of what YaH is doing or going to to do or has done.  

For example: YaHWeH is saying, YaH Causes to be (doing or has done) -- thus, YaH is identified as Creator.  This is also seen in our Savior's Name -- YaH shua is to say, YaH is savior, or YaH is salvation or any other variation that says YaH is our Savior, our salvation, our creator.  This demonstrates the argument over the last part of the Name is a useless exercise -- while many argue over the definitive part of His Name not seeing the true meaning or the Name that actually united all of these variations.  Remember, YaH U or O Shua said that He came in His Father's Name?  

The true and One Name is staring everyone in the face while everyone argues over the definition

of His purpose.