It won't catastrophically fail and take out half your house or anything if that's what you mean.
I would not keep one closed up in a small cramped cabinet though. This is just me though, most people have no issues with them so long as it has some room, and a little air flow, so the heat does not build up too high. As stated, a Milwaukee regulator is a good entry level point, but if you take into consideration the inherent issues with a 110volt solenoid, and that fact that they only come with a six month warranty, then IMO it is better to spend a bit more on a better product. I own two AquariumPlants.com regulators and I would recommend them. They come with 12volt solenoids and one year warranties. The needle is a little touchy but once dialed in mine have stayed consistent.