When I saw Zig Markers "Wink of Stella" glitter brush pens, I thought "OMG best thing since sliced bread, take my money NOW". Since playing with them, though, I'm a little more reserved.
Pro side - the glitter is GLORIOUS - this scan does not begin to do it justice. It's probably the sparkliest art supply I now own.
They are pretty hard to blend - you have to be very very quick, as they dry fast: but it's do-able. The blue flower center is blended with clear, and it didn't dirty up the clear brush, so that's a big plus.
Con side - see the blobs of ink? Yeah, these suckers leak. Like a sieve. If you are careful and don't shake them over your work, and store them upright, you could probably avoid the blobs. Myself, I'm messy and will probably make unsightly mistakes with these.
Also, a bit hard to get a consistent ink flow.
Conclusion: First off, why did I have to buy EVERY COLOR (ok, not brown, who needs brown) when I hadn't tried them yet? Because I'm a sucker, that's why, and I love new art supplies. So my recommendation is to try a color or two and see if they are your cuppa. I got mine from Jet Pens, who I love (and are a mom & pop). I will probably get some use out of these, but they are sadly not better than sliced bread - not better than toast, anyways.