I really like comfort wheel's they're one solid piece of plastic and super easy to clean. plus the silent spinners aren't "silent" i personally think comfort wheels are quieter then them. I wouldn't get a wheel smaller then 12 inchs either. good luck!
We got a 12" solid plastic wheel (it's anything but silent, haha) a few days ago and Tara has been going somewhere as fast as she can ever since! She absolutely loves the thing. I know "Wheel Tail" is a possibility, but she loves it so much that it's worth it.
Willow, on the other hand, wants nothing to do with the thing. I guess it's hit or miss depending upon their personalities.
IMO, Comfort Wheels are SO loud! My rats have one and my mouse has one, and when they're both being used at the same time, I can hardly stand it!
I don't have any experience with Silent Spinners, but many people like them. I love my Wodent Wheel, it's so quiet the only noise it makes is from little rattie feet hitting it while they run. Precious!