I haven't stayed at the Adora, but on a map I see it's not in what I'd consider an ideal location in Ljubljana. It's in the south part of town, though it's a small town and still quite walkable from there. It's probably too far to walk from the train/bus station, if that matters to you. The bus/train station is on the north side.
I usually stay at B&Bs or private rooms in hostels in Ljubljana. Last time, in May, I stayed at a cheap place near the Dragon Bridge. (Private room for only 40 euros/night - not particularly nice but fantastic location.) The time before that, I stayed at the Grand Hotel Union, which is in what I consider the ideal spot in Ljubljana, right in the center of it all. The hotel is usually pretty pricey but sometimes offers last-minute discounts if they aren't booked - which is why I booked a night there. The hotel itself was nice, a bit stuffy perhaps but the view of Ljubljana from the room was breathtaking. But on a map, the Grand Hotel Union is a good reference point.
Consider the Slamic B&B too, another place I've stayed. It's slightly closer than the Adora to the center of town, but it's on the north side and walkable to the train/bus station.
I too would check out Booking.com for lodgings. This is early before next September so I'd probably book something refundable/changeable. Most places on Booking.com are refundable this early.