Run for your life. ACASS has one of the worst if not the worst reputation in the business. For all of the reasons mentioned before, stay away from ACASS. I have several friends who have been screwed by them, I have been called by them and will not touch one of their contracts... Look elsewhere. You will not have a problem finding a good job without their help.
I would consider looking elsewhere, ACASS has a very bad reputation with all of the pilots that have flown for them. They will screw you over in the beginning or at the end. If things start going wrong for them, they will not take care of you. I know a lot of pilot who have been screwed by ACASS. In this industry there are two types of pilots...Those who have been scrwed by ACASS and those who will. Just beware...
Hate to end this circle jerk but I have flown on and off for them for over 3 years now and they have paid every penny that they owed me. I know the rules and read the contract before they sent me out, and they did what they said they would.
Read the contract and know what you are signing but they did everything they told me they would and this is on many, many different airplanes. Am flying one for them right now and no issues.
There are a lot worse contract companies out there (there is another Canadian company on the Western coast I would run from) but from where I stand, and the other 15-20 pilots that I know currently flying for them they have few if any issues.