Here goes the external debate again haha, I tend to feel the debate goes more towards the cost of the setup. For those that have mechanical skill etc it might not be an issue, however some like myself that have no skill and rely on professional tradesmen to do it can take a good hit price wise, with not the greatest gains for all the expense.
It's more of a knee jerk reaction to the "external" will fix all argument that has prevailed recently, when in reality in some cases the external might not fix the problem/issue at all. Or be a great cost for some when greater gains can be gained elsewhere. Externals definitely have their place as I for one have one, however was needed for the setup as the internal gate wasn't up for the task.