If you are forced to change, I'd recommend the 5.11 XPRT 3.0 boots. Very similar fit and feel to the Salomon 4D GTX and have eVent lining which 5.11 claims is BBP protective as well as waterproof. I love my Salomon 4Ds for wet-weather wear but I find I am wearing the 5.11s more and more often. I've not been a fan of 5.11s other footwear iterations but these, so far, rock.
I would have never tought of 5.11 as a choice. Are those boots really a good choice?
Currently I use a pair ot OTB Bootistan. I am not thinking of a replace because those are quite well for any terrain and weather. But the new Salomon line looks great. Unfortunately good equipment and fair price is not something easy to get here in Spainistan; most of the time you have to order outside if that's a chance.