The objective answer is that the LS does just about everything well, it can't even be argued otherwise. An LS is smaller than any OHC V8 whether european, american or asian, makes 300-350hp stock depending on variant, and will last for a couple hundred thousand miles easily. The aftermarket is massive and cheap and you can make 500hp with a heads, cam, intake ("HCI") build with even the mediocre early LS1 bottom ends. They can sound good if you don't just retard mode straight pipe it or put flowmasters on it, and other than LS7s with valve issues they don't really have any consistent serious issues. An LS1 is a ~480lb engine (iron block are ~105lbs heavier than AL and the truck accessory mounts are heavier too). They're just a good all around choice. A good frame of reference for you is that a dressed M50 is almost 460lbs and is longer and taller than an LS, and an M54 is somewhere around 40lbs lighter than an M50 (the block is a lot lighter but a B30 crank is quite a bit heavier than a B25 crank). The other famous swap engine, the 2JZ, is about 515lbs dressed with a single turbo. So LS engines are very light for what you get, which is an easy and fairly cheap 3-500hp engine with great low end torque that will last and fits in just about anything.