I'm a young gay guy and don't have many chances for the real thing, so almost a year after buying this, and almost a year of frequent use, I'm a huge fan. The smaller is, like the name says, a perfect plug. I could slip it in with little prep and just a small quarter sized bit of lube, get my pants and all back on, and head out for the day (made lectures a lot more interesting). For the bigger, my first few times, I needed to wear the smaller for a while first and use a lot more lube, but once it was in, it filled and stretched me like I wanted. Lazy nights-in, I would take my time, do some "kegels" (I think. It wasn't using my anal muscles, but more internal and forward. I can do them without my anus penetrated, so I think it's kegels), and just enjoy the feeling until it's too much with the vibration. My prostate is pretty shallow, I guess, and with the larger of the pair, the region between the two bumps was right there for me. Using the pulse setting, it would almost milk me, and I loved it.
My only complaints are after use.
1: the vibrator. Maybe it was a flaw in the one I received, but I'll show the button cycle: off - low - high - pulse - low - high - pulse - low and so on. To turn off the vibration, I have to actually unscrew the battery compartment and with my fingers covered in lube (and more), that's a tough task.
2: getting the larger out is pretty hard. The depth of the base is pretty severe and not that flexible, so getting my fingers around it is difficult.