Amethyst versus Nagaoka MP-150/MP-200


Does anyone have any experience with these two carts, by any chance?  I have the Amethyst and I've used it for about 40 to 50 hours now. I think it's a beautiful cartridge, and I'm a fan of Sumiko in general, but it doesn't hit the spot like some of the other carts I've used.  So I think I'm going to sell it and buy something else.  I've had my eye on the MP-150 for a while.  Would be curious to hear folks' thoughts on this cart, especially from anyone who has heard the Amethyst, too.  (Also, if anyone has thoughts on what a good selling price for the Amethyst would be, please let me know.)  Cheers.
three_paws

If that's how you're defining pure, I'm a bit confused, as I don't think the Amethyst replicates the original tonality with some magical accuracy.  I think it gives them a warmth that isn't inherently there.  That's actually why I like it so much.

Btw, I'm not sure what in my post has given folks the impression that this is my first cart, etc. I have several TTs, amps, speaker pairs, etc. I am just asking about these two specific cartridges, not for advice on how to shop, how to build a system, etc.

@three_paws 
noromance , do you find the AT bright/fatiguing at all?
Nope. I have the 750 on a 401. However, give it about 20 hours. It's not in the same league as my Deccas but it is fine with good frequency response and detail. 
Just a note here. A detailed cartridge is not bright or fatiguing. That is a system issue. Shying away from them is covering up another problem.
@noromance , sure, but I never said all detail is inherently bright.  High frequency detail, or excess of it, certainly can be, especially when the cart lacks tonal balance.  That's not a system issue.
@three_paws Probably the wrong adjective, which is my fault. I was struggling in finding the best word choice earlier. I also sensed that, like me, you have different systems going on. This thread is an isolated subject.