I have the XRS, and another ac member living near me had the MaxHemps... I have had a chance to listen to both with the same amp, and its difficult for me to decide which I prefer although they are very different in some ways. Basically, the 8" drivers sound full and warm, but the 4.5" drivers are faster, a little more detailed, and probably more neutral overall.... but they can be pretty ruthless with poorly recorded material sometimes. My preference changes with mood and what kind of music is on. Your choice of equipment and cabling would probably be different between the two. We tried a couple of ICs with both speakers, one was a single strand of 28g Jupiter silver for the signal wire, otherwise it was a copy of the anti cable IC. The other was 8 strands of 28g copper in a counter-rotating helix. The copper IC sounded lot bigger and warmer and was clearly preferable with the XRS, but the silver IC was a better match for the MaxHemps, the colder, clearer sound of that IC balanced the warmth of the Max's better.
I think the new 6.5" Alnico driver speakers (theres a bookshelf and an XRS model, like the 4.5" line) will split some of the differences, and it should be better than either the 4.5" or the 8" ferrite motored drivers. I think the bookshelf model is right around $2k, I will eventually buy a pair. If I couldn't afford those, I'd go with the Super5 for 1/2 the price.
Also, the amp makes a huge difference, Louis can recommend some good ones... KT88/6550 or 6L6 SET and EL84 amps seem to work really well with the Omegas. I honestly wouldn't consider a SS amp unless its a temporary measure, or you have a lot of cash and can afford Pass or RWA amps, for example. I'd rather have the 4.5" driver speakers and a good amp than spend all my cash on the 6.5 or 8" speakers...