Ultra comfy. They have incredible lateral grip without making you feel like you are in a pair of vice grips (Like the Focus ST Recaro's or the Mazda RX-8 R3 seats). The leather is thick but compliant. The headrest is supple. The seats adjust fairly easily. The front back of the seat is manual, as is the height adjustment, but the reclining is power. In cold weather they go from cold to warm in 4:38 seconds.
To me the STI seats were too open and flat and allowed too much movement (although the material probably did a great job of holding you in). But to me they were closer to benches than sport buckets, the Focus ST is the other extreme where you felt wedged in where the seat was constantly present. The R was the honestly the perfect spacing, pading, etc. You do not notice the seat until you go into a curve and then you just do not move, the start to feel the seat do its job without being uncomfortable at all.
Yes, they were one of the reasons I bought the car.