About $1000!? I am kinda curious about actual comparisons too.
I haven't used either, but both have received praise from different groups.

Often, that more expensive, the less you hear about it, the more affordable, the more you hear about it.
I own Sequoia 11 and it is the best DAW I've used so far but I am also interested in mastering so its why I migrated to it as well. I wish however, Sequoia had a dedicated controller, which is on my severe want list. I simply detest using a mouse anymore. Its so awkward to me.

I notice, looking at the Nuendo 5 media, they have a really sweet looking controller. Nuendo 5 is around the corner so I'm a bit premature on asking this comparison but there must be Nuendo 4 vs Sequoia 10 users that have compared the two which would be interesting.

(excluding Pro Tools),
We usually get what we pay for.