The 4.6 is a heavier engine. It is not lighter than the 5.0. That's part of the reason the SN95 is heavier than the Fox body. It's just smaller cubic inch/stroke wise. You can also really tell the difference between the two engines' physical size just by looking at them. The 4.6 even looks larger. Much wider.
I've had the 5.0 and I currently have the 4.6. Personally, I like the 5.0 better. Much more and cheaper priced aftermarket parts and is much easier to make faster than the 4.6. The 5.0 is sooooo much easier to work on yourself. Everything about the 4.6 is expensive. Power wise, the 5.0 has more torque down low, but the 4.6 can rev higher. Basically the 4.6 has a higher power band than the 5.0 so it takes it a bit longer to get going than the 5.0. Of course this is talking about the 96-98 4.6. The new ones work the same, they just have alot more power.
------------------
1996 Mustang GTS