Which is the better choice here?

 

I can get a good deal on an older metanium (I’d upgrade the gear to brass). The metanium would still be cheaper but would get very close to the cost of a new 150 curado. 
 

which would perform better? I’m planning to use it for chatterbaits and crankbaits. 

Casting is apples to apples to me.  Both are smooth and great casters.  I feel the curado 150 palms a little better for me, and it sits closer to the rod if that matters to you.  It's been a minute since I have had a 16 met (actually sold it when the curado 150 came out), but iirc it felt a little more solid in the hand, but not by much.  The curado also has 6 brakes opposed to the 4 on the met.  I think the curado looks much better cosmetically, but that is a mute point.  For retail cost of the curado, you can get a 20 met from japan sites for approx $30 more.  But that will have a smaller spool and smaller paddles than the US version.  If I were choosing between a 16 met and a curado 150, I would choose the curado personally.  Which I did and now own 5 of them.  If paying retail, imho the curado mgl 150 is the best reel on the market for the money.

Buy a new JDM Metanium.  You can get one for around $250 or less shipped.

^This if the spool size is correct for your needs.

When given the choice always go made in japan

I like aluminum hande side plate reels for winding in higher resistance baits when I can.  It's not a must have but a nice to have.  I'd be looking at a Bantam self.  

That 16’ Metanium was/is the OG. Loved how it palmed and casted! Looked awesome too! The newer Mets seem tiny compared to the 16’

If you feel the need to change the gears in the Met I’d just go with a Curado. Performance in that application is 6 of one , half dozen of the other. 

I've never used the previous gen Met but the current one is a an absolute gem of a reel for me and I absolutely love it.

 

I also have a Curado 150mgl and it is great for what it is, like really great. It surpasses the Met in some areas.

 

For one I find the breaking system in the C. more reliable and better developed, I think this is in part because of the 6 pins, but perhaps more so they have tuned the way the dial works. I feel on the Met even very small incremental movements on the dial have a massive effect on the breaking profile which leads to a very narrow range of useable adjustment. The Curado, on the other hand, allows for much more fine tuning and, overall, the breaking experience leads to some pretty long casting and a lot of fun when you want to dial it in for a "free spool" type of feel when chasing that last few percent of casting distance. 

 

I'm not often chasing that anymore, mind you, and so I find myself more than comfortable just setting and forgetting either reel and using it, within it's normal fishing parameters, to great effect and with long casts. non-magnetic breaks feel much more natural to me and I appreciate that I cannot feel the magnets pulling on the spool.

 

Back to the current gen Met, it is a far better reel than the Curado in every other way. It is more solid feeling, rock solid gearing, smooth, and has a wonderful "resistance" that makes every turn feel identical, whether you are hopping a jig or winding a spinnerbait with alot of drag in the water. The Curado, by contrast, feels less natural doing just about everything. It doesn't feel like the reel is helping pull that big spinner or winding that big fish or what have you. It just doesn't feel "strong"?

 

I'd choose the Curado 150 for jerkbait fishing every time. There is a feeling to this reel, that I get from alot of well made, more cost effective reels, that isn't quite a feeling of "smoothness" but a feeling of "nothingness". I like this feeling of "nothingness" very much when picking up slack with a jerkbait. I'm also getting better casting distance and a more reliable breaking profile as I desribed above. But for everything and anything else I'm choosing the current gen Met. 

 

I'm sorry this doesn't directly address your question, but I hope it helps none the less.