What's up with the Alfa Romeo 147's 'Selespeed' transmission?

Car enthusiasts have been drilling the Alfa Romeo 147's Selespeed transmission. As an option on some 147 models, this was an automated manual gearbox, promising the engagement of a manual with the convenience of an automatic. It has become known for being problematic, and divisive. Others praise the sporty feel when working correctly, though owners and reviewers have experienced everything from jerky shifts to complete failures. It's a debate on whether the Selespeed makes the 147 driving experience better or worse, whether the Selespeed is more (or less!) reliable than a traditional transmission, whether the Selespeed was ahead of its time or a flawed concept. Some say that it can be worth mastering the Selespeed's idiosyncrasies to get a rewarding drive, others say to steer clear.