We stayed with our family of four at this Hotel over Christmas and had a marvelous time. All personnel is warm and friendly and trying to make your holiday as perfect as possible. Special thanks to the director, helping us out with our snow chains and Lenny the driver who drove us to the piste every morning and picked us up whenever we were ready.

This was our fourth time staying in this particular area of Flims. We ended up staying here as the hotel we normally book was full. This was a tad more expensive.
We had booked one of the suites the hotel offered - the balcony and views were very relaxing and a nice place to sit. The mini bar was complementary and re-stocked on a daily basis (unheard of anywhere else on this planet...!) which was a very nice touch. The room itself was around average sized as we have stayed in other suites in the same area - basically double a standard room, one half serving as a living room with the bathroom separate, and the other as a bedroom. It was also a nice that the TV was on a bracket next to the archway between rooms, so you could simply swing it between the areas if you wanted to watch in the bedroom or living space.
The room itself was very clean, as was the bathroom.
The spa facilities were OK - not the best in the area by far. The pool was tiny and not really meant for swimming in - rather more of a large jacuzzi. There was also a shortage of loungers, so if we were there and sitting on both of them there was no room for anyone else. There is a steam room, 'experience' shower and sauna too. There is no outside spa facility here (plunge pool, heated outdoor pool etc) which is present at other hotels.
The food was good - we only had dinner in the hotel once and went out for the other two nights we were there. There is lots of choice on the dinner menus, and the breakfasts have a wide variety of hot and cold options to suit almost everyone.
There is also a well-stocked bar and lounge area, as well as (slightly questionnable) live music on a nightly basis.
The hotel organises lots of activities in the local area, and also gives a weekly planner which tells you what is on in the local area and where, as well as tips on what to do if you're not always wanting to go up the mountain. The staff were very helpful on every occasion we spoke to them.
Overall a good hotel - just let down a little by the spa facilities and value for money. No real negatives about any aspect of the stay.

We have been coming to Switzerland annually for the past 30 years and have experienced probably the same number of hotels. This has to be one of the best. The staff were extremely friendly and willing to help out with any enquiry. The food was of a very high standard and the waiters were faultless with a real willingness to please the customer. Travelling with our adult daughter we feared the accomodation might not be adequate. We need not have worried. We were given an extremely spacious room with excellent cleanliness and decor. I cannot reconcile some of the comments posted by others. They must be awfully hard to please. My only comment is that the hotel's website does not do it justice.
There is a list of regular weekly events organised for those who wish to take part, and the area of Flims is a real hidden gem. Our first trip to the Caumasee 10 minutes walk away just took our breath away. We loved it so much that we are considering buying an apartment in the locality and this hotel would be our first choice without question if we need somewhere to stay in the process.

Imagine that you fall while skiing and break a couple of ribs -- an injury that is sometimes described as the second most painful common human experience after childbirth. You and your family obviously need to cut short the vacation and get home for treatment. Would you expect your hotel to exhibit understanding and sympathy for this unfortunate turn of events? If so, don't plan to stay at the Sunstar in Flims.
Sunstar's response to my wife's agonizing condition was to inform us that we'd have to pay a 279 CHF "cancellation fee" for the remaining night of our original booking. (That's 75% of the original room price.)
Our objections were met with the following "logic": 1) We could have selected the cacellation insurance during the booking process. But of course every consumer group (i.e. Consumer Reports) advise against such policies. 2) We receive a credit for another stay at the hotel within 12 months. Now really, after this treatment, there's no chance we'll come back to this hotel?
With our final billing, the hotel quoted their standard cancellation policy. In other words, they refuse to distinguish between people who just want to leave early and those who have to leave early. From a business perspective, you have to admire their cleverness. They've instituted a policy that allows them to profit from the injuries suffered by their guests: Either you (foolishly) buy the cancellation insurance, or you pay the cancellation fee.
Contrast the hotel's response with that of the "Free" rental shop where we got our ski equipment. As soon as I told them my wife was injured, they cancelled the remaining charges for both of us.
Oh, about the pool: They call it an "Erlebnisbad," which usually designates a complex with several pools, waterslides, etc. This hotel offers a tiny pool (4X5 meters, as noted on the website). As my son (the pool fanatic) said, "It's like a large bathtub."