(: ASA, the better ABS. I guess it's ok for a mounted enclosure. One thing that I consider a test for quality - cheap plastic enclosures/shells (esp. shells for tools). PC/PA6/PA66/PC+ABS/POM(!)/PP+GF/HDPE all good (esp. with fiber reinforcement for PC/PA). I can't recall the last time I have seen ASA, aside quick connect garden fittings.
Out of curiosity: what else have you considered as material?