spears to hold them. halberds to kill them.

I have used bulgarian brigands a little as mercs. Uphill they are as fast as kataphractoi. good as skirmishers but run easily. Trebs are better imho. Longbows even more so but costly and run out of ammo real quick. Trebs & longbows can melee quite well while brigands are pretty weak.

Best bet is to take a few in some custom battles and make up your own mind.