We chose to embark in Vancouver on July 9th and cruise south to north because we were flying to Kodiak, Alaska after the trip to see our son who is stationed there.
I have read dozens of reviews so I thought I would offer my opinion. We had no expectations as this was our first cruise. First off....the weather. Amazing. We cruised from July 9th to the 16th. We saw sunshine and clear blue skies every day. We were told by our guides that the weather was "unusually" very good. Sea state for the entire cruise was either rippled or glass. I can only presume these factors would add to a great experience.
Embarking: We chose to get there early after staying one night at Sutton Place in Vancouver. We arrived just after 11:00 and we were eating at the horizons buffet by noon. Absolutely no problems. I could imagine that if hundreds showed up at once...it would be slow.