I'm pretty fussy about my RSS readers, but Gruml is looking pretty impressive already. Without a lot of bloat, bells, or whistles, it takes Google Reader's information and presents it in a usable format. (I can't stand Google Reader's presentation itself.)

Gruml rapidly found my subscriptions and updated them quickly and smoothly. The layout is the familiar 3-panel format (with an option for a 3-column layout). The rest of the layout is also familiar and intuitive, with a reasonable amount of customization tucked away if you want it. It offers a handful of Styles for viewing articles -- not as many as some more established RSS clients, but you'll probably find something you can live with (and though I haven't looked into it, I assume these are CSS stylesheets and can be extended if you want).

In the short while I've used it, it's been stable and responsive.

Although Gruml on its own doesn't quite measure up to my long-term RSS client (VIenna) the Google Reader integration bumps it up several notches. It's an impressive feat for a pre-1.0 release, and I'll definitely keep an eye on this.