Right, odds are someone won't switch between one 500hp V8 to another. But if I gave you a 500 hp Gen III Valiant for instance, assuming you never have driven a 500 hp LS Valiant, are you going to say, "Nope, this one isn't good enough because it's more expensive," or "No, this definitely doesn't feel like an LS. An LS would be so much better in X, Y, and Z." My point is, at the end of the day, whether you swap to a small block, Gen III Hemi, LS, or whatever V8 you can choose, if they're making about the same power and are about the same weight (within 100 lbs to disclude a big block or Gen II Hemi) the car is going to feel relatively the same (like a V8 muscle car).
Again, I'm not hating on LS swaps. I've seen a lot of cool ones out here in Cali. They're great daily driver/performing engines. I've thought about attempting one someday in the future. But if I were to do one, it would be in a Chevy (interchangeable parts and easy swap kits are readily available) or something different that would completely change the dynamics of the car completely (like the 240sx or RX-7 I mentioned before).