Most reviews of The Hermitage tend to be posted by overseas visitors to New Zealand, so I thought it would be helpful to post a review from the perspective of a Kiwi normally resident overseas.
We visited Aoraki-Mount Cook at possibly the least propitious time of year - a rainy August mid-week - having booked one of The Hermitage's NZD299 package deals (available from their website) for double room standard accommodation, a la carte dinner and breakfast, along with another couple. Despite some rain on the first day, we had a good experience there. We would recommend The Hermitage, albeit with a couple of provisos discussed below.
The Hermitage has excellent amenities for an establishment so far into the South Island's hinterland. These are of an international standard. In particular, our double rooms were very comfortable and all have views of Aoraki-Mount Cook (when it pokes out from behind the cloud, that is). Comfort shouldn't be confused with luxury, however, and those seeking hedonistic pleasures like a swimming pool or hot tubs are out of luck. But then, you are staying in a national park and with amazing views of Aoraki-Mount Cook and the Mueller glacier.
Service at The Hermitage on the whole was generally great. Very friendly folks of several nationalities work there. Despite arriving as two married couples though, the desk person allocated us two rooms with two single beds each. We had our rooms changed without a problem - although the queen-sized doubles are actually the single beds pushed together and using larger bed linen. On the upside, they're really comfortable beds.
Our rooms had a flat screen TV and cable channels, mini bar, good shower and a balcony, which faces Aoraki-Mount Cook. The rooms are contemporary in decor.
How was the food? The buffet brekkie is to be wholeheartedly recommended - one of the best we've had anywhere. The a la carte dinner was not especially outstanding, although service was very good and the wines by the glass on offer were decent. Although it might seem so to the traveller, The Hermitage's restaurants and bars are actually not the only eating options in Mount Cook Village. Though gastronomic options within 50km are limited, it's worth noting here that the Old Mountaineers Cafe and Restaurant a few hundred metres away in the Village has yummy food and a more informal atmosphere.
The bar in The Hermitage (the Snowline Lounge) was excellent, and a roaring fire (with marshmallows to roast provided) so fierce we had to back off a bit. Prices were not particularly exorbitant, and there were a good range of beers and whiskies (at least one Japanese single malt was included in the spirits line up).
There are plenty of activities that can be booked either from The Hermitage's activities desk (in its fairly well-stocked but touristy shop) including walking tours, scenic flights, glacier kayaking (also possible from the cafe in the village) and so forth. There are all sorts of walks of different durations and levels of difficulty, some of which are suitable for undertaking in the rain. And, of course, there is amazing mountain climbing in the area.
Even in rough weather, Tasman Lake is a 10-minute walk from an un-sealed road in neighboring Tasman Valley (usually accessible by 2WD vehicles). This is a must-see, and offers great views both toward the Tasman Glacier and down-valley toward Lake Pukaki.
There are interesting displays in the foyer of the Sir Edmund Hilary Outdoor Centre, which is located within The Hermitage building.
One thing that's actually thoroughly worth doing is a session in the Sir Edmund Hilary Outdoor Centre's modern planetarium, which is accompanied by a live commentary. On fine nights staff will follow this with a night excursion to look at the stars through telescopes. The Hermitage is located in one of the world's best night sky "dark" reserves, so this is an opportunity not to be missed. (We only did the planetarium part because the weather outside was cloudy and wet.) If an astronomy lecture sounds horrifyingly tedious then don't be intimidated. It was very entertaining, and special recognition is due to the staff presenting lectures there for communicating so much in plain language. Just be aware: after a big dinner it can be slightly difficult to keep one's eyes open in those in the comfy seats in the dark…
Downsides? No free wi-fi in The Hermitage, which continues to really surprise us about many "high-end" places to stay in NZ. Come on Hermitage, time to catch up! Internet in hotels we believe should be regarded in the same way as hot water - as a utility. While we respect the right of hotels to charge for high-speed/wide-bandwidth connections, being able to check one's e-mail and conduct a bit of travel research on the web should be possible without extra charge.
Overall, The Hermitage offers decent value for the price we paid for a stay in a special place (NZD299 per night - drinks and activities extra). In high season, of course, The Hermitage can be much more expensive and you will pay considerably more for "superior" or "premium" rooms. But if you want to get away from it all to amazing views and access to wilderness while enjoying a high level of comfort, The Hermitage ranks high as a place to go.
Just bear in mind that there are much cheaper (and way more basic) spots in Mount Cook village to stay in - including the YHA and cabin units - if you are on a strict budget, and there is at least one alternative venue and eat at. Whatever you do, don't forget the camera!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.