Between the two, I'd go with the Krell. It's an oldie but goodie and I've heard it; sounds quite good. Also, it's built like a tank, if you ever need service you shouldn't have a problem then down the road, if you decide to sell it, you'll probably get close to what you paid for it.
As for the Melos, I have two friends who've owned their gear and both had ongoing problems. One finally gave up and just mothballed his unit. Resale will never be as good as a Krell and you'll probably have a hard time unloading it down the road.
