There are several problems with this question. One being that you cant declare @Start 2 times.
The other being that the answer is wrong. They both perform equally. I have executed the query as is (though with the @Start thing dealt with). With the 2 queries in the opposit order and one at a time. And the time is always roughly 100ms result (give or take 10ms).
I get the same execution plan (2005) for both queries. So im hoping that someone with more knowledge then me can enlighten us.
The above ramblings can be ignored. Rewriting it i had missed that there are 2! selects. Running the code from the link was "better". And had the effect that was being pointed out.