BPM, APM, VORP are all encompassing stats that do not ignore defense.
BPM and VORP are both box-score metrics
It has been stated numerous times these statistics have limited value when making an argument that attempts to measure defense...
There are limitations on all box score stats – if the box score doesn't measure a particular contribution, a box-score-based metric can only approximate that contribution. This is not a great hindrance on the offensive side, as nearly everything of importance on offense is captured by the box score (only missing things like screen-setting), but on defense the box score is quite limited. Blocks, steals, and rebounds, along with minutes and what little information offensive numbers yield about defensive performance are all that is available. Such critical components of defense as positioning, communication, and the other factors that make Kevin Garnett and Tim Duncan elite on defense can't be captured, unfortunately.
BPM should not be used definitely for defensive metrics...
Box Plus/Minus is good at measuring offense and solid overall, but the defensive numbers in particular should not be considered definitive. Look at the defensive values as a guide, but don't hesitate to discount them when a player is well known as a good or bad defender.
For the sake of this argument it should be noted that, VORP is highly based on BPM, so citing VORP is merely accounting for time on the court. If both players have similar time played, you're simply double counting.
Moving on to APM, which isn't a box-score metric; however, APM is useless for this comparison. Anyone citing APM over RAPM/RPM, especially where the two disagree, would really - really need to explain his methodology because this makes next to no sense.
Let's use last year's 2-year APM for these two players which is at least useful data, but again, not for this discussion.
Kevin Love 5.49 > Aldrige 4.97... with a std.er of 3.31 on Love's regression, and ~2.9 on Aldridge's.
So mathematically, we don't know who is better or worse from looking at APM and further calculations are necessary to draw any real conclusions..
That's why I cited RAPM and RPM has being more relevant to the discussion... Stats that are probably the best overall aggregate metrics for comparing two power-forwards.
That's also why I said you cannot
"easily" make the case that Love is better than Aldridge, because there is ample statistical evidence to demonstrate that Aldridge is the better player.
I'm fine with saying they are nearly equivalent, however; I think the data supports that.