Not deep, but sufficient I think. Comfortable leading WI3, have led WI4. Rainier last year, Cotopaxi and Chimborazo in Feb, Pisco and Chopicalqui earlier this month. Many, many steep snow lines in Colorado over the past 3 years. My partner is relatively inexperienced but hasn't been intimidated by anything I've thrown at him, including Whitney MR, Rainier FF, Ecuador volcanoes, Mt. Russell E Ridge, etc.
I'm on a glacier kick right now, and the Baker and Shuksan routes mentioned are looking like fun alternatives.