I have that machine At 5.5hp in my opinion it's just enough to get the job done but isn't really big enough. It works ok but I think the main problem with it is the EPA approved non-adjustable carb. Mine surges and I can't wait for warmer weather to take it off and drill the jets. I don't have anything heated.The worst one we tested was a Troy-Bilt 24" with the 179cc MTD engine. That thing was wheezing in 5" of snow.
I also have a Estate ES825 that's a 8/25 and that is much more reasonable. It doesn't go on it's governor nearly as much.