Nothing significant has changed since my earlier responses other than the initial enthusiasm for these techniques has waned in the plastic surgery community as the potential has become more clear over time. The risks are really no different one way or the other except fat grafting usually takes more operations to reach an endpoint that is more likely to be lackluster.
Re. DIEP, you should know that it is ALWAYS possible... mesh is NEVER necessary, and full protection of the muscle is ALWAYS possible (see APEX flap section on my website) so if you've been told something different you've either been misinformed or mislead.
Hope this helps,