The first and second generation of hybrids share more of their appearance with the genestealers than they do with the host species. Superhumanly fast, beastial, clawed, yet also able to wield weapons and guns thanks to their human heritage. They are an ungodly blend of species in short.
The acolytes are somewhat mutable in the sense that they can be built in a (small) number of ways. Plus, one can take mobs (is that the right collective word for hybrids? I'm not sure!) of up to 20 to scare opponents. But more fundamentally, these hybrids are good in close combat. Given their price tag, that might make them some of the best bang for their points value in the game realistically.
They probably want to be either tooled up for close combat and in a large mob for use with some of the special genestealer rules and formations, or kept to ten or below models for use with Goliath transports. Either way, they are going to be solid in close combat and able to rip through most enemy squads. Think of them like orks -- but better.
Poor save. Poor toughness. These are further reasons to buy in bulk!
A few builds to consider.
20 Acolyte Hybrids, Leader with lash whip and bonesword (185 points).
For use with formations and genestealer cult special rules (cult ambush!).
9 Acolyte Hybrids, Leader with lash whip and bonesword (97 points).
Add in a Primus and a Goliath and you have a recipe for destruction. Add a rock cutter or rock saw to taste.
5 Acolyte Hybrids, 1 heavy rock drill (60 points).
A small squad for taking out tanks. Perhaps even road bumps. Several of these are rather scary when they appear rapidly all over the place.
10 Acolyte Hybrids, 5 hand flamers, 2 demolition charges (145 points).
Take a goliath. Throw the charges. Flame what's left. Return to the Shadows. Cult Ambush. Could be nasty.