I had that same cab, along with the 410tvx. I thought they were decent. The 115 has a Black Widow speaker, which has decent mids. It wasn't a great stand alone cab in a rock band.
The 410 sounded great...I used it mostly by itself. This is a much better cab then the 115...it produced more low end then the 115, nice mids that really cut through the mix, and decent highs...although the tweeter was harsh.
Both of these cabs are heavy !! Peavey lists the 115 as 94 lbs, it feels much heavier. The 410 is even worse, very solid. I pulled a muscle in my back from carrying these cabs. After that, I traded them.
Overall, I think you can do better then the 115 as a stand alone. Paired together, they sound great, however, that's $800...you can find much better cabs at that price. I'd say go with the 410 or keep looking. They're plenty of deals to be found.