Well, IMHO, Dragon Lords of Melnibone is a half-assed search & replace job done on the Elric! RPG rulebook, replacing BRP terms with d20 terms.
But the Elric! RPG rulebook itself is pretty decent, though much inferior to the original Stormbringer rules (not the new version, which is just Elric 1.1).
So, basically, the setting is actually quite good (though Chaosium's material tends to be of variable quality), but they did an awful adaption of it to the d20 rules. So, you probably will need to do some work yourself.
For instance, they didn't bother to adapt the Elric magic system to d20, but use the standard d20 version. Which doesn't fit the Elric universe at all (though to be honest, the Elric system isn't a great fit, either, but is better than the fire & forget system...).
Another thing - the demon summoning system is broken. Demon summoning is fairly common in the Elric setting, yet in the d20 version, no one would ever summon demons, because it's too costly. To summon, you have to sacrifice a lot of experience, then to bind it, the summoner has to give up 1-3 ability points permanently.
That might fit a very low magic setting well, but not the Elric setting. (The Elric rules themselves rules were also the opposite - the summoner would sacrifice spell points, which refreshed every day, to summon a demon, then a power point to bind it. Power points would improve all the time)
I could go on and on, but won't.
So, to sum up, DLOM is perhaps not a bad book, but if you use it for d20, be prepared to change the rules in it...
