Best PvP Straight Sword is Gotthards, best PvE Straight Sword is this little guy, easily, and allow me to explain why. Most of the other good Straight Swords take a bit of time to grind for or you have to get far into the game before acquiring, but this can be bought by any build the second you reach Firelink Shrine. It's compatible with Chaos infusions, Lightning infusions, Crystal infusions, Refined infusions AND Sharp infusions, alongside a ridiculously low stat requirement. It's light, allowing you to potentially spend less levels on Vitality. It has the lowest stamina requirement per swing of any Straight Sword, allowing it to be swung many times more than the alternatives before having to recharge. It has almost as much AR on a quality build as a Lothric Knight SS, and it has the same moveset meaning it has the rolling poke (which is the better SS rolling attack). All of these factors put together make it dwarf the other Straight Swords in accessibility, versatility, and DPS. Basically, if you don't care for PvP pick this thing up. The range makes it kinda **** for PvP but It's still entirely usable in that department if you know what you're doing, just go for Gotthard's if PvP is your game though lol.