Been waiting for this for a while. It's not too bad at all. Haven't stress tested it yet, but it's nice to once again be able to read articles on my Kobo Nia.
I can have instapaper on my E-ink tablet at any time because it runs Android, not a proprietary OS.
Just got the update on my Kobo.
Tested with a free Instapaper account and that seems to work fine.