I have one that is like a halogram (shimmer) - smooth like a ribbon. I have used it successfully. I do put the roll a long way from the machine and kinda of hand unwind it so it flows nicely (like I do with invisible thread too) and give it some room to flow. I have not tried and actual metallic thread....

I always put metallic thread on a thread stand and have never had a problem. My machine is always at 600 stitches per minute anyway so I don't need to slow down my machine more than it already is at. I cann ot tell anything about it since I only use Madiera thread.

I have found JennyHaskins metallic threads flow off the spool very nicely--BUT I am not real pleased with the stitch out---seem very thin---Floriani has done well----C&C was AWFUL>>>>I have not tried Sulky---sounds good enough to try. God bless you.

I have used it before. It is really pretty stitched out, but it tends to twist a lot. I solved that by using the packing peanut trick and putting the spool at least 3 feet away from my machine on my thread stand. I was stitching a large area so I did have to take it off the stand and unwind it once, but I thought it was worth it when finished.

I've tried the sliver thread and didn't have much success with it... you do need to have it feed "flat" into the machine, which mine wasn't willing to do, LOL!
I've had great success with King Star Metallics and it's available in the UK.
I use a thread stand about 18" away from the machine - this seems to give the thread time to "relax" a little before running full speed through the needle. The tension is at 2.8 (the default setting)