The Balkan Jewel Resort is located outside the city. It's a 15 minute drive to Bansko with almost nothing in between. So if you don't want to spend your entire time at the resort, you'll have to take a shuttle to the city.
The resort is split up into four building, unfortunately they are not connected with an internal walkway. Ergo you have to exit your building to go to the restaurant, the front desk, the gym/massage room/ jacuzzi, etc. Think about that in the winter; you'll have to wear a winter coat just to go for breakfast or pack a bag to go for a massage.
We went during the off season. We were in the Amber building of the resort. All the lights in the building were almost always off, so we would have to turn on the lights when we entered/exited the building and our floor. The building was deserted. It's just strange for a hotel.
The sole restaurant at the resort isn't very good but it's your only option if you don't want to get out.
I regret picking the Balkan Jewel Resort. I strongly recommend picking a hotel in Bansko, around the city center instead.