I went ahead and bought one today. So far, out of 30 or so images, there are no keepers. Even in what I thought was decent outdoor light, either the shutter is at 1/60, or the ISO pegged at 1600 with a reasonable shutter speed.
I'm sure that in bright direct sunlight I could get a 1/500 shutter speed. but 1/30 and ISO 650 is pretty noisey.
I've set it up in raw now, but that really did not noticibly help with post processing. We have good weather coming, so I'll set it up on a tripod. I'd use a remote release, but it doesn't have that either. A self timer is worthless for small birds, the move too quickly.
I did experiment with the aperture. At 135mm its already at f5, and at 200mm, its f/5.6. At 600mm, its f/6.5.
There will be a learning curve, but its going to certainly be limited in its ability to shoot any images in low light at any focal length over 100mm equiv without a flash.
Here is the best of several, I'll shom some more as I ger better at it. I have a couple of weeks to return it if it doesn't pan out. There is no feather detail at all, its lost in the ISO 640 noise.
Its 1/60 sec, f6.5, ISO 640. I've adjusted it as much as I could, but the detail isn't there.