I know Sigma's Foveon Raw file processing software has its issues. It's slow. And on some OS platforms it can be a bit buggy. Me? I actually have gotten used to the tonal controls, white balance (which is quite good by the way), noise reduction, contrast and shadow controls etc. and find them to be effective. So much so that I open the Tiffs in LR and aside from cropping followed by a little tweak with the exposure along with a 'paste-able' clarity and vibrance setting I use, it's pretty much ready to be converted to jpg for printing.
But the thing I like most...is the moment during the 'development' when the RAW X3F file suddenly 'materializes' right before your eyes revealing all its the Foveon '3D' magic and razor edged sharpness.
I simply never get tired of it. In fact, for me, it's like the first time I saw a black and white image emerge in a developing tray. Every time.