The packs were really underwhelming. It felt like there was no feedback whatsoever when you activated one. Speed didn't feel very speedy, there was no sound I could tell associated with it, like you get when you activate speed adrenaline in UT2k4. If I was watching better I guess I would have seen less damage with shield pack. Repair seemed to do virtually nothing. or maybe it was just the chaos of an arena that those packs seemed wasted on for demonstration purposes (not that a multiplayer game is any less chaotic).
I would have liked some way of going back and looking at some of the instructional messages on the weapons and packs, and the area around which you can activate a pack from the ground is quite small and the packs and weapons are not easily distinguished from each other. I can imagine walking back and forth trying to figure out what I'm activating and then I'm dead from enemies.
In multiplayer you want some easy kills? Just drop a couple packs and kill people off as they stoop to scrutinize the pretty shiny penny.