Consider these two sentences:
 Being pressed against the wall, he struggled to break free.
 Pressed against the wall, he struggled to break free.
I've recently spent some time reading grammar resources relating to participle clauses. To cut a long story short, the conclusion is this: participial-gerund clauses (or present participle clauses) are always simultaneous with the main clause (unless introduced by the perfect 'having'), and past participle clauses can be either simultaneous or non-simultaneous (stative and habitual past participles are almost always simultaneous, while your ordinary dynamic ones are generally non-simultaneous).
With this information, I'd like to know which of the participles is preferred in the above examples—in your personal opinion, of course. Example 1 is indisputably simultaneous, but Example 2 can have past or simultaneous interpretations (i.e., 'He had been pressed against the wall' or 'He was pressed against the wall'). The effect may be the same, but I'm curious what others think.