I've had great luck with my Hog D3 1st and Hog Classic 2.0 2nd stage reg set. Good for cold water diving, even if that's not an interest, breathes really well, love the turret feature of the 1st stage and so far has held up really well over the last 4 years that I've been diving it. For the price, it's definitely worth consideration. Aside from some rental regs by Mares and Scubapro, I've dove an Atomic Z2 as well and honestly I'd take my Hog over that because it just breathes better. Can't comment on any other regs because I have no experience with them so my advice may be worth exactly what you paid for it.
Just something else to think about....if your wife has a history of jaw strain/jaw fatigue from holding the 2nd stage in her mouth, you might consider having her try out a full face mask. They are a bit more cumbersome and take a little bit to get used to, but once you get comfortable with one they're really hard to beat. No leaks, no fogging, no jaw fatigue (because there's nothing to hold in your mouth), no dry mouth, can breathe through your nose or your mouth depending on how you set it up, can add in coms if both of you have them. A wealth of benefits, but also a few minor cons. They do add a small amount of buoyancy, they are a bit bulky (at first) and they are definitely a bit more involved when it comes to doffing & donning, especially underwater. Certainly not a good idea to dive without a backup mask in a BC pocket just in case. And they are quite a bit pricey. But if you think about it, if you buy one of the more expensive masks (Atomic, Scubapro), those can run almost $200. Say you spend at least the same amount on a 2ng stage reg...you're already at $400. You can get a new ffm for about $600. So again, just something to think about to help solve the jaw strain issue. I'm a huge supporter of them, as mine was the first piece of kit I bought outside of mask, snorkel, fins, boots. So if you get a chance, maybe demo one in the pool and see what you and your wife think.