... so are the two methods relatively equal in execution time, and therefore the ultimate decision is preference of the coder?

For 99% of what I do, clarity outweights performance considerations. So for clarity, I've adopted the following conventions:

1. For object methods, always shift $self, and use array assignment to put any remaining arguments into variables. The shift becomes a visual clue that the sub is an object method.

2. For constructors, I always shift the package name. If I'm interested in any additional arguments, I use array assignment to put them into variables. Typically, though, any arguments are a hash to initialize an instance.

3. For non-object methods, use array assignment.

This leads to code that looks like:

sub new {
    my $pkg = shift;
    bless { default => 1, @_ }, $pkg;
    # @_ might override 'default'
}

sub method {
    my $self = shift;
    my($shoesize) = @_;
    ....
}

my non_method {
    my($height, $width) = @_;
    ...
}
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Code that's consistently written is easier to read, and code that's easier to read is easier to optimize. YMMV, or course.