That's what I meant by "reasonably," but perhaps I should've said "relatively." Meh, the joys of posting at midnight.And I'm really referring to most of what we see the background extras do rather than the actors who played Lennox, Epps etc. - I know that much of what they do isn't realistic.
Cos according to the behind the scenes stuff on the DVD, Bay mostly just told the off-duty military personnel about what was meant to be happening and just told them to respond as per their training. As you said, as realistic as it gets if the army were fighting giant space robots.
And the military were shown as being somewhat effective and not utterly useless like in most other TF series. Anyway, it looks relatively realistic to me, but admittedly I've never served so you would have a better appreciation than I would.
But I watch a lot of other movies where soldiers are fighting monsters (which is really all the Decepticons ever are in the live action films) and you see scenes where soldiers lose their cool and do utterly stupid things that get them and/or their teammates slaughtered. In the TF films we see the the military responding to the Decepticon threat as trained professional soldiers - at least, that's what it looks like to me (again, the background extras - the main actors behave far more amateurishly, screaming and carrying on etc.).