I have a somewhat 'ratty' copy of this lens, with a smear on the front element, somewhere in the house. Need to pull it out to try on one of my digital bodies.
Was never one to go ass-end over teakettle in search of great bokeh, but this lens has it in spades. At wider aperatures, everything behind the focal point just melts very smoothly, no swirlies, onion rings, nor anything else jarring. Quite compact too (52mm filter).
The biggest selling point I think is the compactness and the feel of the lens. It's just matches easily with any digital bodies. I don't think it's quite as sharp as 105 2.5 wide open but it's definitely one size smaller