Yes. Maverick has dual regs. The wildcat mk3 bt has dual reg too. But FX says that the max reg pressure is 160 bar. So let say you push the second reg to 160 bar. You'd have to set your second reg higher than that. That means the second reg is over its max recommended pressure.
When I watched AEAC channel, Steve was interviewing competitors at RMAC (did I get the competition name right?), some of them say that they delete the second reg.
Regarding consistency because of the presences of dual regs. I'm not sure. I had a 177 FX Dreamline with one reg at 140 ish bar shooting the KO slug at 985 fps. And the single reg was doing fine... With the dual reg, I'm not sure if the shots are more consistent because it depends how the gun is tuned. If the tune is right, the dual regs might be contributing to more stability from shot to shot. But for me it's hard to discern if shots are consistent because of the tune or the dual regs. Probably both, but dual regs doesn't mean that the second reg is bulletproof. Pushing it too hard and it will leak.
I recall that I read somewhere or watched a vid (I can't remember where I got the info from). The guy says that we have to remember that any gun that is caliber convertible is designed for 177 up to whatever the max caliber is. Most shooters are probably opting for 22 to 25 cal and they don't tinker. So it makes sense that the manufacturers design their guns around the specs for those cals out of the box. Once we tune, we might exceed what it can withstand. That makes a perfect sense to me.
As for other PCPs, I have no idea. I only have a SPA P35, RTI and FX wildcat mk3 bt. But... The new, upcoming RTI Mora looks damn good. You might want to look at the reviews of that bullpup after it's been released for about half a year to see if it's shooting well and it's robust, if your not in a hurry. I would like to get one of those but it's my out of budget.
If you want to wait for the Mora or any other guns, but you want to shoot an airgun ASAP, a P35 might be an option. As
@JimD says it's a good budget gun. And I can attest that out of the box, it's shooting well and you can adjust the trigger easily. Mine broke after I tried to tune it (same problem, it's hard for me not to tinker a gun), and am currently waiting for a Huma reg. I think if I had left it alone. It's still be alive today.