Anyone using new 16-50 on NEX 7?

I just received the lens yesterday and am somewhat pleased with it.  Not great but not too bad either.  Some vignetting and distortion but I always shoot raw and process so no big deal.  More important to me is small size for more portability.

My lens expands very quickly but takes some seconds before retracting when turned off.  Not irritating, just very odd.  Does anyone else using this combination and if so, is this your experience as well?