I love the Snowpeak Ruins. Though not my favourite dungeon in the game, it is in my top 4 (Behind only the Lakebed Temple, Forest Temple, and Arbiter's Grounds). In terms of difficulty, I certainly do not find it difficult. I'm not calling it easy exactly, but it was rather simple.
The main thing that gave me trouble, besides the enemies, was the Ice block Puzzle, which I have since memorized. It does have some clever puzzles, like transferring the cannonballs from room to room, but they were pretty much all really easy to figure out, they were just time consuming to do. The enemies, however, are a different story. The freezards gave me so much trouble when I first played the game, and so did the Chillfos (especially the one in the entrance room, when you jump across the chandeliers). The Mini Freezards were just annoying.
So, overall, not a very difficult dungeon, just time consuming, with some rather annoying enemies.