I've heard a lot of people like witch elves, but too many never think executioners are great. (but always an ASF horde)
See, to make executioners even halfway decent, they need the banner of hag graef. But they can't take it, so you spend a lot of points on a crappy unit (death hag), with the banner. She can die super-easily and then things aren't good at all. If you run into anything with ASF then you are really screwed. Now they will strike at I order, and be vicious, sure, but BG wouldn't be in hordes even if they could. They are meant as an evil hammer to decimate the enemy. They shouldn't ever flee, that is what ld9 stubborn does for you, and you will kill a crapton with s4 armour piercing.
The exec. unit has to be inordinately expensive to be even decent, which is the problem. You are favoring it to bring it up to par, and even then I don't like it. 8th edition made hordes viable and strong, but not for 12 point models that become largely ineffectual when a paper character dies. There are lots of small effective units - high elves and warriors. Hordes are a way to make weaker infantry punchy, or go deathstar with elites. But to each his own.
Having said that, I've seen them, and they are powerful and can draw a lot of attention.
But if you are starting out, you could avoid all 3 until you figure out which you like as they are all super expensive. (5 for $33 in the USA last I checked, might have gone up).