If you have been on Cruise Lines and then on an Ocean Liner, what was the real difference in your experience?

Anyone here done both? We have done cruises, and since we travel to Europe for business and pleasure sometimes, we are thinking of taking an Ocean Liner trip. We know it's a "different" experience, but would love to hear from someone that really has done both and can describe what to expect that is "different" about it.

Thanks.