Torch Mobile makes a big deal of Iris Browser's customisable user interface on its website, but this turns out to be a bit less exciting than you would expect. The customisation options seem to relate to keyboard shortcuts rather than being able to move around buttons or functions on the browser's main display.
However, if you are using a device with a keyboard then the browser does allow you to map any function to any keyboard shortcut you like. This is done from a clever interface where the command is listed in a window at the top of the screen while keys are shown at the bottom along with tick boxes to set up Alt, Ctrl and Shift combinations. It's all very quick and easy to use. Lots of keyboard shortcuts are already set up by default. For example, to zoom in you tap X; to zoom out you hold shift and tap X; to see an overview of open tabs you press 0; and to bookmark a page you hit Ctrl+D.
The main problem with the browser at the moment is that it's still a tad unstable and seems to be very demanding on your device's resources. You need a lot of memory available to run it effectively without it regularly complaining that it hasn't got enough. And while it was reasonably fast on the XDA Zest, it felt very sluggish to use on the Touch HD. For example, scrolling around a page sometimes involved long waits for the browser to fill in gaps in the graphics.
Overall, we really quite like Iris Browser. Pages look excellent thanks to its top-notch rendering quality and the auto-zoom mode works really well. However, the software still feels quite buggy and in our experience can be quite slow to use on some devices. At present we'd describe it as showing lots of promise rather than being a browser that's ready for prime time. Our advice for now is to stick with Opera 9.5, but keep an eye on Iris as it may have a lot to offer in the future.