We have two in our 3-car garage - I installed myself in 2004. Ours are the screw drive models. Both doors are insulated. They've worked great and are very quiet. When I bought them, I wanted "a good one" which is why I picked the Excelerator - it was the top of the line at the local big box at the time. They also came with a crazy number of openers between the two units - like 8 total. The fast open/close was just a bonus, or so I thought.
Once installed (and after every power outage), they run at slow (normal) speed the first time you cycle them so they can find the start and stop points. I was immediately impressed with how smooth and quiet they were. After that, they speed up. Once they ran at the "Excelerator" speed, I didn't like them as much. Faster door speed = louder door movement. Also, it REALLY yanks the doors up - to the point where I wondered about extra wear and tear on the doors. Plus, I'm NEVER in a big enough hurry to get in or out of the garage where I can't wait the extra 5 seconds for the door to go up. I called Genie and asked if there was a way to disable the high speed. They told me to cut one wire on a specific resistor on the circuit board, and that would do it. I can re-solder at any time if I choose. They've been running at regular speed for 6 years and have been no trouble at all. Only complaint, the light covers don't fit very snugly and sometimes fall open.
Let me know if you need any more specific info - good luck!
