Your source is definitely guilty of poor research. Several "facts" are definitely incorrect or explained by Tunguska researchers. I'll resoond only to the ones I've heard or read specifically about.

2. Trees were blown down in a non-spherical pattern, and some of the blow-down was rotated. An air-burst would produce a perfectly spherical shock wave.

The butterfly pattern has been simulated by using a specific trajectory. This statement is flat out false.

3. Trees show evidence of being burned after they were broken, that is, the heat arrived after the shock wave, which is inconsistent with a high-energy air burst.

I have heard the reverse. They were burned for only a brief period of time as if lit then blown out. This is consistant with ignition by radiant heat followed by a shockwave blowing out.

4. Some trees near the supposed epicenter survived. With a 40 megaton air burst, everything near the epicenter should have been incinerated.

This has also been simulated. Appealing to common sense versus published experiment makes ones research suspect. A little more thoughtful common sense would reveal that a force directly downward is unlikely to push something sideways.

6. No significant fragments or dust have been found, which is important even to the comet theory, as comets have a considerable solid component (probably chondritic-type material).

Totally ignores the heat and resulting melting involved in such an explosion

7. An unusualy sky-glow was noted in Siberia and many other areas for several days before the event. A comet tail would be too tenuous to produce such effects, especially if the comet were not visible prior to the exposion.

The glow was after the fact not before.

The strongest argument against the alternative is that the author doesn't have his facts anywhere near straight. This guy appears to have gone to the EG school of journalism. The facts are generally consistant with an airburst impact although some details have yet to be adequately explained. But then again, the butterfly pattern was a big puzzle initially as well that was solved decades ago.

Regards,
Mark