My experience is that 6.1 Sol is a little behind Opus 5.5 but it’s in spitting range. Their cost per task is generally higher, but if you’re on a quota plan the difference in cost doesn’t really matter until you’re paying API rates.

Both get the job done these days. I still hate Opus 5.5’s output, 6.1 Sol does an acceptable job of doing a second cleanup pass to it.