Raynox 6600 barrel distortion

So, I'm not sure if this is what I should expect or not, but I just bought the Raynox 6600 wide converter for my G6. I've read and studied that the barrel distortion should be very low. However, based on my experience so far, this is more distortion than I would have expected. I've studied the pictures on lensmate's website... so I'm not sure if I just have a bad converter, or if this is what I should expect.

The first picture is obviously not great composition, but I was particularly surprised by the right edge of the fireplace and the light in the upper left-hand corner of the picture.

Since the second example is a landscape picture, the distortion is less obvious. However, there is slight vignetting in the upper corners.

I do mostly landscape pictures anyway, so I could probably live with it if I need to. And I do know that zooming in slightly helps to correct some of these problems. However, I didn't imagine the full-wide setting to be quite this severe.

Would love any feedback from those 6600 users out there...

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All wide lenses distort if they are not straight and level to the subject.
The raynox would be verry good in this situation. your sample is neither level nor straight.
you have no chance like that.

I can see very little evidence of barrel distortion, though I do see the amount of perspective distortion I would expect from any camera pointing slightly upwards with a wide angle lens.
As to the vignetting are you using the correct lens tube and lens hood? Do you have a filter attached as well?

Actually your sample pics still look rectilinear to me. Note that the right edge of the fireplace is still a straight line. If your lens is prone to barrel distortion then this would be presented as a curve. I have the Raynox 720 and it shows much more barrel distortion than your 6600.

I have friends who have the 6600, and they all report a bit of vignetting. The solution is to back off wide zooming a bit and all is fine.

Thank you Terry and BottomBracket... I think that answers my questions. So the key is to shoot buildings, interiors, etc. straight on, rather than at an angle. I actually took some shots later - with the camera pointed straight ahead, and level, and everything was squared up! And you're right, Terry...I believe I had a filter on the landscape shot - so that's probably what the vignetting is from.
Thanks again!
Stephen