I am very opinionated.
I have had bad luck with several different flavors of Armalite AR10 -- all mag related. US Army AMU recommended several fixes to Armalite to fix their mag problems, the simplest was coating of the mag with Robar NP-3 - as they had done that to about 100 mags and saw a dramatic decrease in magazine related issues.
As such I would not buy a system that uses the Armalite Mag.
In Canada our SR-25 rifles are not civilian avaiable, beyond older guns that where around pre stupidity period.
DPMS and Remington (which is based off the DPMS gun) are about the only options in Canada.
As such I would get one of those, and try to put one of our (KAC) XM-110 URX front rails, and a good trigger from someone.
Magpul will be selling their PMAG-LR for $20.00 USD RETAIL
Given the gouging and screwing on the 5.56mm versions it will likley be a $40.00 mag by the time it gets to civilian hands.
Secondly since Wolverine is the Magpul and Armalite dealer -- I think you will find him about as hesitant to bring in