One of my elec. kilns is AIM (27" deep). I bought it about 10 years ago and it is still in great shape. The elements have only been replaced twice, amazing since it is fired couple of times a week alternately with my other kiln. It is fully automatic and the main regulator that cycles it on and off has always been noisy. It has been replaced 4 times (cost $100.00) due to the poles wearing out. They are moving parts. Every new one I've installed has a loud buzzing sound. It is not very pleasant to be around when it is firing. If I ever purchase a new elec. kiln, I'd get any of the suggestions here but would add the Paragon to that list. The electrician here offers some great advice about the load you pull when firing.