Thinking about a TWSBI

[AndrewGWU]

I was thinking about purchasing a TWSBI 540, but in looking into them it seems most all I can find in a M nib is the Amber. Apparently they are coming out with a 580 model soon and 540s are getting harder to find. The 540 is only $40 with FS on amazon currently.
This leaves me with a few questions. Does anyone know what the improvements will be on the 580? Does anyone currently have an amber colored TWSBI and if so, is it the yellow that shows on all websites, or is it actually more amber?

 

[RichieRich3902]

I'm waiting to see what the 580 is all about before I buy my first TWSBI. I don't care for the stories of the 540 feed leaking and the other problems they are said to have. For me, if the 580 doesn't fit the bill, I'm going to try a Mini with a stub nib.