Until I purchased an HD DA 55-300 (the last screwdrive version), my longest lens was a Pentax SMC A 70-210 f4. Not quite as sharp as the 55-300 but the extra stop of light is useful and I prefer the colours of the 70-210.
Telephoto lenses tend to have smoother bokeh, even so, I prefer the 70-210's bokeh to the 55-300.
The combination of really poor lighting of the football field and manual focus meant that my "keeper" rate on this night was less than 5%. However, I would have had to use twice as high of an ISO setting if my maximum aperture was f5.6.
Finally, seven Trumpeter Swans a-resting, when the longest other lens I had with me was 135mm, This is cropped to about 60% of the area of the original.