Uhh, they're super cheap even in vanilla. Infinite durability diamond boots made with iron and obsidian that completely negate fall damage. Yeah, one time cost of 12 iron and 4 obsidian is expensive... Of course you can't enchant them but you can get all the necessary enchants with other armor parts anyway. And the gun uses one diamond and an ender pearl to get infinite uses of instant portals. Forget Enderman farms, you can actually accurately aim with the portal gun and not need a crapton of pearls.
Btw, there is an option in the config to have the portal gun use ender pearl dust as fuel but why is that not enabled in FTB I wonder. But even then the boots would be still very OP. IC2 armor is made to replace vanilla armor so you only have to use EU to "repair" them. But why bother when you can get better boots cheaper and without the need to recharge.
The mod is technical and cool but it really needs balancing. By itself it might be fine but in FTB every mod should be in balance so they don't make other mods obsolete.