I have a hard time imagining there's going to be a heap of people who are ever going to choose an indoor range over a great outdoor range, but I have to keep in mind that everyone has their own experiences and a really great indoor range probably comes somewhat close to a really lousy outdoor range.
To me, it seems obvious that indoor ranges have a lot of faults and negatives that I could list:
irrationally noisy, next to impossible to have even a bit of conversation
comparatively expensive, usually paying by the hour
excessive (often necessary) rules and enforcement of same
lots and lots of lost brass
smelly, dirty, cramped
busy & distracting
On the flip side, a decent indoor range gives me a place to shoot when the weather is completely wrecked -- typically in the depths of snow & ice winter hell. A good indoor range gives me extremely consistent light on my sights and target... not always fantastic light, but
consistent light. And the indoor range is basically built around a hanging paper target that allows for affixing, retrieval and replacement right from my shooting point without a range stoppage and a cold range, which is certainly a welcome thing, especially when you're being charged as the clock ticks. I often look at the indoor range as a bit more "serious" session of shooting as the paper doesn't lie and it does NOT reward laziness or lack of effort.
For me, the winter season where I live typically means that 2-3 months are mostly or entirely LOST to outdoor shooting. During these months, I do very much look forward to the kind of shooting I experience on the indoor range, which is, in my opinion, a
FAR different shooting experience than I get when shooting outdoors. And because it's a much smaller portion of the year, I look forward to it.
But if I were forced to choose one over the other, it's no contest and not close... I much, much, MUCH prefer the great outdoors.