Personally my choice would be for the carbine rather than the CQB. I stood in TSE handling one, lovely gun but I just can't figure out what I would use it for.
It's restricted, so range use only, five round mags (but so is most of the competition), and the barrel length means it won't make PF for IPSC rifle (not that there are many IPSC rifle comps in Canada anyway).
I just can't think of anything I could do with a CQB that couldn't be done better with the Carbine. Less muzzle blast, more MV, etc. And the Carbine isn't a particularly long gun.
And whether or not the parts breakages are still a problem or not, the Carbine uses the same recoil system as the rifle, and that is well proven.
One comment on Rich's comments - I personally prefer the mag setup on these guns, I think it's an advantage over an AR-15. My trigger finger is long enough that I can push the lever to release the mag release, so there's no real difference compared to an AR-15 (at least for me). Plus they lock into the gun far more solidly than AR-15 mags do.
I have NEVER had a malfunction with the Swiss Arms rifles that was a gun problem. Lost count of the number with AR-15s.