I own both (no pics handy).
In 2000 I fell in love with the GTS. Not being able to afford anything of the sort at the time, I looked at Corvettes. I really did like the C5 body style, and I'd never owned a real sports car. At the time it was a daily driver (couldn't afford two cars). The vette was a great choice. Good performance, creature comforts, well balanced for daily street life. Sold it for money reasons in 2003.
In 2004 was shopping again for a sports car. Looked at lots of stuff, but I just couldn't turn down 10k off a NEW 2004 C5 that dealers were trying to clear for the incoming C6.
I still have and really like my C5, though it doesn't get much play any more. It is stock power-wise, but has many handling, braking and cooling mods in it for track work. I don't suspect I'll ever get rid of it, we've had a lot of track miles together. I feel like I could track that car in my sleep. It would be like selling a friend LOL.
Finally got the GTS earlier this year.
They are both so totally different... hard to say which one I like better. The Vette seems dog slow now of course, feels like I could smoke a cigarette in the time it takes to get to 60 LOL... But in 103F weather, it sure is nice to have a sports car with A/C that cranks!
I think it also goes to show that many can appreciate the two sweetest sports cars America has to offer. Why not have 'em both!