If that is all U can get - get it - Before I got my P99 compact, I was told that none were available - so I was gonna get the SW99c - but they eventually tracked down the P99c.
I also have a SW99 fullsize - it is my fav gun right now. I even hard chromed it. It is the most accurate gun I have. Now, I did have a fullsize P99 for a short period of time, and I stupidly damaged it myself, so I sold it because it killed me to look at my best gun damaged. Now, I have the opportunity to get another Walther P99 - I should have it Thur or Fri.
The P99 I prev had was a tiny bit more accurate than my SW99.
When I gave up searching for a fullsize P99 and settled on the SW99 in Nov 05, I got it for a great price - $437 new. But, eventually, I still wanted the Walther version once I fell in love w/ the gun so much.
Is it worth it? Only U can answer that - if U think U will eventually want the Walther made P99 too - then buy it now. If you will stop w/ just the SW99 - then buy it. It is really the same gun w/ just a few aestheic differences. But, the Walther does look a little cooler. And, I can't explain that very slight increase in accuracy...