Minions do:

Randomly do their own thing when told to attack a target.  Seems like they follow for a bit, but then get caught up in traffic if there are other creeps around.  When I hit select all minions and right click on a Demigod, they should all follow until they kill him or die. 

Get stuck on walls, towers, corners, etc.

Respond slowly when told to regroup, Spirits do a ridiculious loop that usually gets them killed by towers

Get kited by most decent demi-gods early on without issue and usually become cannon fodder once demigods are much tougher mid/late game

Minions do NOT:

Seem worth it, except for the aforementioned Oak Spirits

Scale well into later levels, most people shrug them off. 

Get many kills for you, and most generals have like 3 skill trees dedicated just to them

Get you experience for killing creeps unless you are near them

I am not much for long thoughtful posts, but can anyone else confirm?