I have now had an opportunity to test them on your behalves by ordering a coffee and vanilla milkshake from Five Guys.
They are narrower than the plastic straw provided, though there was no difficulty drinking the milkshake. There was no unpleasant metallic taste. One thing that does happen is that the straw, being metal, becomes extremely cold, which is marginally an issue.
@ryan1 made the good point that walking around with a drink while using a metal straw is potentially dangerous: if you fall you could impale your upper palate and die a horrible death.
@Randall1028 wisely suggested just taking two paper straws with each drink instead.
On balance I have decided to accept the counsel of them both. The metal straws will be a home-based luxury only.
I think the real solution to the sogginess issue with the paper straws could be overcome by simply coating the straws in some type of waterproof material. Perhaps a carbon based polymer of some sort.
Fine. I order to coddle your delicate fingers, i have invented a new product: straw coozies. Much like the ones that go on bottles and cans, they will be a neoprene rubber that fits snugly over the part of the straw you hold. Available in a variety of colors.