I also find the iPhone (iPeng) SB controller and the touchscreen on the SB perfectly fine as interfaces. Maybe not 'the' best, but they work fast, sensibly, and comprehensively at a fraction of the cost. I can quickly get to what I want and have search and shuffle options as well.
I hear what you say. I've never used iPeng - perhaps that's the way forward. But I recently created a big playlist (7 hours plus)taking single tracks from about 140 albums for a party, using SB server on a PC, and it was not the slickest experience ever. Biggest problem is the delay in refreshing the web interface screen every time you click something.