Thought I would report back.
First off- the MetroEmb.com shipping was SO fast. I ordered on Wed and had thread on Friday. Unfortunately, my machine hated the Metro. It was clunking so loud I seriously thought I had broken it. I tried it with multiple needles, multiple bobbin threads; I rethreaded multiple times, and even recleaned and oiled my machine just in case (though I had done that earlier in the day, so it was clean). It was a disaster- tension was horrible no matter what I did, skipped stitches, and that awful awful noise. So this one is a no. (It is super pretty on the spool though, so shiny.)
Sigma was much better- it wasn't the beautiful purr my machine normally has, but it didn't sound terrible. The tension looked good. Still it didn't run as smoothly as other threads. The price on this one is so good that I might consider it again in the future if money is tight.
Glide was fabulous. They are not kidding when they call it Glide. It stitched so smoothly it was like the design completed itself in no time. I think it is thicker than the Isacord, which isn't ideal for travel stitching, but the travels didn't look bad (though the design I did wasn't great...but that's not the thread's fault.) I'm going to go for this one I think. Biggest annoyance is the spool is wound in the opposite direction of most of my threads, and so the way I put it on my machine I have to dig out a different spool cap.
I also tried ThreadArt's poly and loved it too. Not quite as smooth as Glide but still very nice. I'm adding that to my list for the future.
And, I retested Isacord and still love it.
The photos are of Metro/Sigma (I didn't finish the design with Metro for worry I was going to break the machine- it is the blue/green, the Sigma is purple), Glide (beige), and ThreadArt poly (light blue). Both Glide and ThreadArt were sent to me as a free sample. I expected bobbin size, but they sent me full spools, so that was really nice. BobbinCentral also sent a free colorcard of Glide.