Being in an Omega Circle, I'd imagine you would see more positive impressions of Omegas. That said, is it at all possible for you to listen to both speakers?
Those LS50s are really special, as the many raves and awards would indicate. Though they will not shine if underpowered. And yes, I would imagine that they may not be as compelling at low volumes. But their bass and ability to fill a small room is excellent. An exceptional speaker, but one that will sound different than the single-driver sound. For better, for worse. Very often a matter of trade-offs and personal preferences about what tradeoffs are worthwhile and which are not.
If you read further up the thread, you will see there are those who have heard both the KEF and Omega.
Back in my consumer days I purchased two audio products that were universally praised by the audio press on both sides of the pond. Five star, best buy, product of the year, etc. They were both mediocre sounding IMO and poorly made, and didn't last long in my system. Check out many of the review sites and you'll find the great reviews generally go to those who have the header and sidebar ads on said website. Audio reviewing today is advertiser driven, not market driven as in decades past. KEF, like many of the big names has deep advertising pockets hence gets great reviews. Also, much politics involved too.
At $1500 a pair, the LS50 should be made in the UK under the same strict CE, UL, CARB, etc. type rules that Omega voluntarily imposes upon itself. Sound quality aside, what health hazard do these made in China speakers impose to the owners thereof? Do you think a country that doesn't play by the same rules as the western world as far as "clean" products go is going to provide something safe?