Wow, if that ad is to be believed, then that looks to be a great deal. It's a one owner car, and the owner has obviously cared for it. Definitely worth taking a look it.
If it really is stock and has all that maintenance documented, then that's a great price, and I personally would go for it.
As with most modern vehicles, Subarus are very reliable and will run well beyond 200k miles with proper maintenance and care. I wouldn't consider 175k a deal-breaker if it's been cared for, and it would appear that this one has been.