I recently made the mistake of borrowing a friend's Bose-X headset after my own ANR had stopped working (probably due to condensation forming in it during a flight to Svalbard). I wore the Bose-X for the return flight from half-way up Norway back to Biggin - which was nearly seven hours of continuous flight - and at the end of it I felt like I hadn't been wearing a headset at all because the Bose-X is so light and comfortable. It was a mistake to borrow it because now I want one!
During those flights, I was able to try several different ANR headsets in the same aircraft, and make an immediate direct comparison by switching from one to another. To be honest I don't think the ANR is substantially better than my own headset - certainly not enough to justify the price. But the lightweight comfort of the Bose-X is tremendous if you do long flights of several hours.
If you're only going to be doing bimbling flights of up to an hour or so, I wouldn't bother with the Bose-X: any ANR headset will do (or get your passive headset converted, as I did). If you're not going to be wearing it for long periods of time, then the money is better spent on other things.