I know the OP and most of the other posters in this thread are from the great white north, but wanted to chime in anyway.
Last year I switched to the connectors below after learning some unsavory info about those purple wirenuts.
These are listed for CU and AL wires. The only thing is that you will need to buy and use a torque-limiting screwdriver to install them for UL/CSA listing compliance. They can also fill up a device box quickly if you have several splices to make.
The company sent a free sample connector before I purchased in quantity.
Here is the product link. http://www.alcopstore.com/