I haven't seen an EU in action besides on TV, but a few people here have the BCB.  The BCB is a good medium to medium-heavy oil ball.  It's got an Aggressive Reactive cover, a slight modification of PK18 that was used on the Fuze line.  I'd compare it to the Monster Bruiser, but a pinch stronger.  Good midlane and a strong backend.

The EU, from what I've seen on TV, is a smooth, early rolling, light-load particle ball.  Almost all midlane with a controlled backend.  Medium-heavy oil, heavy oil without the polish.

SH

i just bowled this weekend in our state tournament with both.  
for what i seen they both work well on about the same conditions really it comes down to if u want a ball that flips or or has a good conatant turn. I can use mine on heay to medium both balls but i dont throw them 18 mph either.
Both have a typical lane 1 hit with the Black cherry just a lil more pop because of the flip but u really have to pay attention to see that.  Cant go wrong with either of them.  If i had to choose one i dont think i could i love both.
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doesnt look like im in kansas anymore toto