The Voyager rooms are about 160 sq. ft. We had interior deck 9 (cat.M) last year on the Explorer. I thought there was plenty of room for the 2 of us. Closet was nice size w/storage, small couch in room w/little table too. We went on the Majesty in March, and my daughter had an interior room, it was like a closet, tiny, like 119 sq. ft. We had oceanview (on deck 5 for both), and it was smaller than the Explorer, but was ok for the 4 day cruise. I haven't splurged on a balcony yet, cuz they tell me once you've done it, you won't go without, , but i've gone from interior, to oceanview, to interior, and it was ok for me. Try to conserve $$$ where possible. Hope this helps. I checked the above web site, and couldn't find the Nordic Express room sizes.
NCL Dawn (Repo 14 nite) 11-1-09
RCCL Mariner of the Sea (Mexican Riviera) 4-18-10