Still have my 28-300mm, IQ is similar to the 24-105mm. May still sell it at some point, but I got it quite cheap (used) so that's not an issue - would likely fetch a profit. Going to see how it does on the 1D X first, and since I'll likely pick up a 24-70 II, I'll evaluate at that point the tradeoff between the convenience of the 28-300 vs the IQ of the 24-70 II + 70-200 II.
Mt. Spokane has/had a 35-350L, IIRC he liked it. I know he's posted pics from that lens in a few threads previously. Perhaps he'll chime in...