i learned on acid and still use it to this day as my sequencer. unfortunately thats also to do with having a shit processor that cant handle the reason sequencer and one that hurls abusive noizes at me whenever i use more than 6 midi channels in sx. having said that, i'd still use acid even if i had a p4xe. i just love the layout and the ease of writing. the sound is shit though and i always render all the tracks down to full audio files for use in sx. takes a bloody long time to do a full track though