I own and like both rifles quite a lot, but for the time being, despite a bit of extra weight, the XCR-M will win out over the SG542.
The 542 is a good rifle, obviously as the Swiss Arms line took many cues from it, but I have been having problems with the proprietary magazines for feeding, and have not been able to sort it out yet. Lack of accessory rails to add a proper bipod is a big downside for longer range shooting, as the factory folding bipod really lets it down in the stability dept.
The XCR is an awesome piece, with the one downside in my opinion being weight, but massive adaptability is a big selling point.
The M shoots incredibly well off a bipod with a Vortex Razor HD 1-6x scope for mid range rapid fire. (4-600 yard) With proper optics this rifle is suitable for 0-600 yards, or can be suited to either CQB or long range in particular, the rifle is accurate enough for the long stuff.
Feel free to ask any specific questions you guys may have, I am more than happy to answer, as the rifles are just a few feet from me right now.