We JUST returned from a Honolulu to Vancouver sailing. Even though we hit some ODD weather along the way, the Celebrity Summit rode very well. Felt like glass most of the time,
I was told the ride east to west is a bit rougher, depending on currents.
Cruised Ensenada to Hawaii on Summit May 3. Quite smooth, no problems. Never had to take a Dramamine! Second time we've taken this route - same time of year. Last year we had one day when it was a tad "rocky". We did have a few overcast days crossing the Pacific, but not enough to bother us. I'd do it again.
We just sailed the Ensenada-Hawaii route in February. Seas ranged from, according to the TV monitor, 5-8' which was rated as moderate, to 8-13', which was rated as rough. However, the Vision of the Seas handled the trip well and we saw no need for medications. We would love to do this trip again.