Between the NAD T743 and the Marantz SR5400, in a close call, I would go for the Marantz because of the power of the Marantz. Both have good sound. The Axiom Epic gives no impedance problems. I have heard both the Marantz and NAD (I have the SR5300 and the T763) but have not heard the speakers. I would defer to someone who has knowledge about the particular matching of the speakers and receivers.
The 8 ohm Axiom speakers aren't finicky about which receivers you use. When you use their 4 ohm speakers (Alan Lofft of Axiom) has recommended HK AVR 330, HK AVR 430, or HK AVR 630 along with the better Denons. I am sure the NAD's would be equally fine too, as they are designed for good 4 ohm operation.
What the NAD's often give up in features they more than make up in solid amplification. H/K is similar in most of their models, except they often have more features. A 50-60 watt NAD or HK will play considerably louder than their amp specs, as they have lots of headroom. Most other commercial receivers don't have that kind of headroom and amperage and when they play more than 2 channels the wattage going to the speakers normally drops anywhere from 5% to sometimes over 50%. Also many manufacturers measure their receivers at 1 khz frequency into 8 or 6 ohms, which is an unrealistically easy load.
Gregory: I saw the parallel thread but, as you mention, the Axiom speakers in question are 8 ohm impedance and therefore cause no problem. With respect tothe ratings, the Marantz SR5400 is rated at a true 90 watts per channel. It should have plenty of headroom as you say even over the NAD and the HK.
I certainly wouldn't have a problem buying the Marantz SR5400. Marantz has made some very needed improvements in their amp sections in the last year or two. I remember back in 2001 when the Marantz 7200 was listed as having 110 watts per channel, but tested out at about 30 watts a channel with 5 channels driven. They have definitely remedied their amp insufficiencies on the 5400 and I would have no problem recommending that unit for most any system. Looking at its power curve, it looks like it will even drive 4 ohm speakers well, as long as you don't go over 140 watts, which I think would be incredibly rare.
On these 3 brands I would base my decision on the features and the ease of remote usage. The features you value most should steer you in the right direction.
So I give kudo's to Marantz on upgrading their amp sections. It would be great if many other companies did that on their mid-priced receivers, rather than just saving the good amps on their flagship models.