I'd guess your 300€ budget ($333.54 USD) should well cover the unit & shipping. Sorry to be a too persistent advocate, and I can't even claim experience with your other selections. The WMD/SSF unit looks great, & I like the octave selection switch, but I don't see any explicit description of it as 'analog' - which may or may not concern you. The z3k also has waveshaping which I've often utilized, and even while analog, holds it's tune VERY well and is ready to work on startup (unlike the otherwise commendable Rubicon which sharpens pitch over the first half-hour plus...) Also the visual tuner is actually damn handy, and speeds workflow - perhaps less of a concern if you're focusing more noise applications etc. The Kilpatrick looks intriguing - particularly the waveshaping/PWM capabilities seem unique... I'd just want to check, as with any module, that other people are happy with it's build quality and customer support.

Good luck with your hunt!