Why should I buy one of these? They look pretty good, but are there any serious advantages over the wooden fixed axles I throw?
I don’t count spin time as an an advange because in the videos I’ve seen of people using them, they use them for regular modern responsive play which generally doesn’t require it.
Is it just different colour options? Being able to use regular poly with them?
Well if you suck like I do, you need all the spin time you can get for decent bind chances.
Well, we all suck at yoyo in one way or another.
I would say metal density is a big advantage as well, plus bearing. All the same arguments really. Get a YYF Confusion and see what you think.
How does metal density help?
From what I see in metal slimline designs, they seem to try and work around it.
Sure you can make it more compact. I actually even have two Slimline responsive titaniums but I don’t necessarily recommend that.
The Confusion is a fun throw and plays well. To be honest though I prefer wooden fixed axle for responsive play.
Is the bearing an advantage aside from reduced string wear?
Modern responsive slimlines give you a big performance boost in most areas. For example, you can do shoot the moons, loops, and around-the-worlds and regen directly into a long breakaway or frontstyle combo and cap it off with a strong flyaway dismount and it’s effortless. With wood, it’s not trivial.
I carry a metal slimline 80% of the time. Don’t get me wrong, I love wood yo-yos. It’s fun to do shorter elements and the feel is unique and rewarding. I just think metal slimlines open up the possibilities and make execution of my personal favorite tricks easier.
I think where you’ll see the biggest difference Glen is in the overall feel and play of a metal slimline. Now, I’m saying this as one that hasn’t tried the ones you are making. But all of the wooden slimlines I’ve tried lack some of the stability, and “solidness” in the feel and play of any metal slimlines on the market.
The only slimline wooden yoyo I have right now is a a/Rt Poupon, that I have a greasy bearing in to make it responsive. It’s fun, but it plays completely different than any of the metal slim lines that I own.
edit: Just reread your post and saw that you mentioned your fixed axles. With that in mind I’d second what Brian said 
They certainly excel at letting your knuckles know when you’ve made a mistake.
I may be in the minority here, but I use metal responsives when I know I’m gonna be beating them up, they seem to be able to take more damage than wood and still maintain play quality. overall I prefer regular fixed axle wood though
I thought the OP was asking about responsive play…
Responsives still need to bind and the slower they spin the less odds they will bind. Slower spin and spin loss happens (MUCH) faster on fixed axle.
So they are useful for a combination of responsive and unresponsive tricks within combos. That sounds interesting.
I suppose what concerns me there is that because they can do breakaway or front style combos in the middle of responsive play, the response would be lacking a little over fixed axle?
I’ve found that beating up my wooden fixed axles doesn’t really affect their play quality. unless of course you abuse it so badly that you crack or snap the axle, which needs serious effort.
Another thing I like is because its wood, when you scratch and ding it, the colour of the damage remains the same because the yoyo is the same colour throughout the body.
With fixed axles, regens are your friend.
Not sure I understand that second part
The second part of what I just said?
Yeah about the combos having to do with the response