I agree... I love my Barley Crusher. Even better benefit than the increase in efficiency is the ability to buy grain in bulk - I buy my base grains by the sack. If you're in a homebrew club or there are other local people organizing group grain buys, you can start buying grain amazingly cheap. To give some perspective, I bought a 55lb sack of 2-row for less than $20 - that's about 35¢ per pound! Of course, 2-row is the cheapest, but everything basically becomes dirt cheap - ESPECIALLY when you factor in the fact that you're already using less grain due to increased efficiency.
Just keep in mind when you use it, you want to go no faster than about 120-180RPM (2-3 full turns per second) or else you start excessively shredding husk material.
Also, if you don't own a set already, I highly recommend you invest in a feeler gauge (can be bought in the automotive department of any hardware store for a few bucks). Preferably one that lets you remove the blades and reorganize them. This will allow you to accurately measure and set the gap between the rollers. This not only lets you experiment with various gap settings, but also allows you to change it for grains that require different gap sizes, and then afterwards set it back perfectly to what you were previously using for barley and wheat.
Perhaps most importantly though, a feeler gauge allows you to make sure the gap is perfectly equal on both ends of the rollers, which really helps maintain a more consistent efficiency since every single little grain will always receive the same crush, rather than widening along the entire length of the roller. Maybe even doubly important for Barley Crushers, because the one problem I had with mine (no longer an issue since I got a gauge) is that the "default gap", which is set by the factory and indicated by the line etched on both of the adjustment knobs, was not only way off from what they say it's supposed to be (0.036"?), but WASN'T EVEN CLOSE to being equal at both ends - I believe the "calibrated" lines on my adjustment knobs (which is of course what it is set to when you receive it), set the gap on my roller to something like 0.043 on one end of the rollers and 0.051 on the other end, which is crazy. And I have yet to talk to a BC owner who's said that they checked the default gap and found it to be very close to what it's "supposed" to be.
But most importantly... enjoy the thing! Crunching through a full hopper of dirt-cheap bulk grain on my very own mill continues to be extremely satisfying every time I use it!