My first ever cruise was 7 days on the Spirit. Personally, I enjoyed it greatly. It is an older ship and does show a little age, but the bathroom in the room we were in was much larger than I expected. It was an interior room and had a walk in shower with a glass door...Our traveling companions had the same size shower, but I don't know what cabin class we were in.
We found lots of places to be alone and play games as well as lots of places to be with other people.
I suppose it depends what you are expecting...but we had a great time and have been on two cruises since then and have two more booked...all with NCL