I prefer the Tubus Nova and Ergo (stainless and cromo versions of the same rack) over the Tara. The reason is that the bottom of those racks is flatter than the Tara. In my opinion the Tara, while simple and strong, is not a very good design down below for actually holding panniers securely. For Ortliebs, the main tube of the Tara is too thick and means you have to jam the lower hook on there in a way that bends it. For bungee based panniers (i.e. hook on the bottom), the curvature of the lower part of the Tara means the hook wants to slide off the rear.
The Tara used to have a hole on the bottom, with a little eye bracket that you could screw in to hook bungees onto. But they have discontinued this. Apparently this wasn't actually supposed to be for bungee hooks at all, but rather older style strap based panniers, which Tubus felt were not worth supporting any more since (in their view) nobody uses those panniers any more. But they didn't seem to realize that this little eye was also useful for bungee hooks. Now it's gone, the hook can very easily just slide off to the rear.
I much prefer the Nova and Ergo, for the following reasons:
1. The bottom is flat, which holds the bungee hook much better.
2. The Ergo and Nova have an additional hole option for where you attach the top bar, which makes it easier to get your rack completely level. The picture below of the Nova on my Co-Motion Americano looks slanted, but that's only because the bike is up on the kickstand - when both wheels are on the ground, the rack is dead level.
3. The diagonal strut near the bottom is flattened and works very well for Ortlieb style panniers which have the hook.
4. All the tubing on the Ergo and Nova is "regular" sized, not oversized like the Tara, which means it is easier to hook onto with both bungee and Ortlieb hooks on any part of the rack. There are also more strut options to hook onto, which gives you a more stable backing for the pannier (e.g. you could use two lower hooks on an Ortlieb, hooking onto different struts, whereas with the Tara there's just the one big thick tube).
About the only advantage of the Tara seems to be that it's rated for a slightly higher load, but in practice I don't think you're going to carry anything on the forks that will challenge any of these racks anyway.
And between the Ergo and Nova, I prefer the Nova - it's stainless, so no paint to be rubbed off, exposing the bare metal to rust. You can get really good price on the Nova from wiggle.co.uk, and super-fast delivery too (they did 4 days from UK to Eureka CA, and shipping was free).
And, for whatever reason, the Nova which I got recently still has the little hook eye on the bottom, which is nice (see pic below).
Hope that helps,
Last edited by NeilGunton; 06-24-10 at 10:43 AM.