Well, SPADs are pretty much extinct in the "top level" combat competitions. They are fragile compared to a well designed foam plane, SPADs are often heavy, and the wingspans of the top planes are 64-72", anything shorter is making your life harder.

The Slasher can fly slow, every good combat plane can. A first rate combat plane has a wingloading in the 12oz/sqft range or lighter. That's lighter than a typical trainer, so they actually float better than just about anything out there. (turning radius is mostly a function of wingarea. Other factors matter, but wingloading is critical).

Btw, keep in mind that most combat planes aren't using the fragile white foam you see in sport planes and coolers and such. We are using higher density stuff, 25 or 40psi rated, or using EPP which bouces. It's nothing like the white foam.

I have only seen the Slasher a couple of times, but it seemed fly ok. I have a lot more experience flying against the Ripper in SSC class, where it's an ok plane, holds it's own, but is out-performed by some of the better designs.