My dictionary says that "in regard to", "with regard to", "regarding" and "respecting", and "
as
regards" (no "to") are all acceptable, though the last of these is
disparaged by some stylists. "in some respects" is thought to be
much better than "in some regards", the latter being rejected by most
of the usage panel. No notes were provided for "in respect to" or
"with respect to".
CJ