The first example is likely to be seen in some circles as poor convention as it makes the input value look as though it is in Hungarian Notation.
Many code completion and formatting tools will encourage you to use
this in order to be explicit in your use of variables. I tend to agree with this, as it makes it very clear at a glance whether the variable is local or belongs to the class. Of course, if you are keeping all of your methods nice and short on the order of only a few lines, and the method parameter lists are likewise quite short, then it may not necessarily be an issue for you. Personally I still prefer to see
this liberally sprinkled around the code, as this makes variables stand out distinctly due to the syntax highlighting that most modern IDE's provide you with, and the less I have to actually look into the code too deeply, the less distracted I get when jumping around the code while trying to solve complex logic problems in my head.
With that said, the compiler won't care a jot which way you've written your setters. Your colleagues on the other hand may have differing opinions, so it is up to you all to decide which approach you might wish to enshrine in a coding standard.