Having owned a slant 4 and having been in a few including a 280 bhp HSR chevette I would disagree about the sound being hard to beat.
I think my V6 sounds nicer. My brothers old Tvr with a cologne 2.8 ford V6 sounded beautiful too.
A sweet V8 is always nice- talking quad cam lexus v8s or other high revving V8s. Then there are flat plane V8s which sound amazing too.
But each to their own - so long as you don't give up and end up scrapping a Viva. Enough of that happens already.