I have to think the Mac will hold its value better...
Well, only you can determine which will be better for your Tyler D1's.
I agree with RW that the Mac will hold it's value better, and be easier to find. That being said, I'd go with the Clayton M-300's. Wilson Shen's amps are something special, almost tube-like in sound. I think Wilson Shen and Stan Klyne are two solid state designers whose equipment a tube fan like myself could live with.
Hard to go too wrong with those options. I can say the Claytons make everything sound like music. I thought about replacing them with some high powered Cary amps a year ago and the Carys, while good amps with very good bass, were not even close in musical enjoyment, IMO. These are very different companies with Clayton being basically a one-guy outfit and McIntosh being a larger, more established audio company. However, I think the build quality is very good for both. Wilson is a great guy and a no-nonsense designer. With Clayton, your money will go into the parts and resulting sound quality, every aspect is robustly designed and constructed to last for many years. Wilson has even been known to deliver his amps, if you are not too far away. Packaging of the heavy Claytons is excellent, as it appears to be for the McIntosh also. At this price level, it would be nice to hear them first, but you mentioned you are purchasing used so that may not be an option.