It was quite common for the dealer to give me a GS when my K's were being serviced. I never bonded with the GS. Compared to the K they felt tall and heavy with a complete lack of power. There was no "excitement" when riding them in the way there was with the K. Where the K felt like a wolf in sheeps clothing the GS always felt like a sheep in sheeps clothing.
As said by Andy, after the loaner GS, the K always felt like my ares was in the air, at least for the first couple of miles. The K also felt "tiny" after the GS, which, in reality, was something it never actually was.