What you need to know? Don't go through a 20' gate with it if it's 8 wide row.
If you want you can come run some 12 row wide them the 8 will seem small and you'll fell like you aren't getting anything done.
More gates, more power, more parts, more road, than 4 or 6 row.
Six row used equipment tends to be the highest price here since there are a lot of smaller irregular fields between the swamps.
How big is your average field ?